Rheumatoid Factor: The Most Remarkable Autoantibody in Rheumatoid Arthritis
The European League Against Rheumatism (EULAR) launched the ‘Don’t Delay, Connect Today’ campaign in 2017, continuing into 2019 for World Arthritis Day. The day is a global awareness day focusing on promoting the symptoms associated with rheumatic and musculoskeletal diseases (RMDs). Moreover, the world awareness day focuses on the importance of early diagnosis and access to care 1. Randox Reagents fully supports the importance of early diagnosis which aids in the early implementation of effective treatment plans, aiding in improved health outcomes. On this World Arthritis Day, Randox Reagents will delve deeper into rheumatoid factor (RF), the most remarkable autoantibody in rheumatoid arthritis.
Pathobiology of Rheumatoid Arthritis (RA)
Rheumatoid arthritis (RA), “the most common systemic inflammatory autoimmune disease” affecting 1% of the global population, is characterised by fatigue, synovial joint pain, stiffness, swelling and destruction, with severe symptoms resulting in disability. Whilst the exact cause of RA is unknown, it is believed that genetic and environmental factors play a role in triggering the disease 2, 3. Differences in the human leukocyte antigen (HLA)-DRB1 alleles (proteins with a critical role in the immune system) have been identified as a genetic variant for RA, observed in >80% of patients, particularly in those testing positive for RF. Moreover, those with variations in the HLA-DRB1 who smoke, increase their risk of RA. As RA is more common in women (2-fold increased risk in women compared to men), hormonal influences are an area of active research, however, an inverse correlation with breastfeeding has been identified. Women who breastfeed for >13 months aids in reducing the risk of RA compared to women who have never breastfed 3, 4.
The pathophysiology of RA involves various signalling pathways and immune modulators (effector cells and cytokines) as indicated in figure 1. Joint destruction is caused by the intricate interactions of immune modulators, beginning at the synovial membrane and encompassing most IA structures, with synovitis caused by both or individually, the local activation or influx of mononuclear cells, including: B cells, T cells, dendritic cells, plasma cells, mast cells and macrophages. Consequently, “the synovial lining becomes hyperplastic, and the synovial membrane expands and forms villi”. The neutrophils, chondrocytes and synoviocytes secrete enzymes that degrades the cartilage in the joint whereas the osteoclast-rich area of the synovial membrane destroys the bone 4.
Figure 1: Schematic view of (a) a normal joint and (b) a joint affected by RA 4
Clinical Significance of Rheumatoid Factor (RF)
Interestingly, elevated levels of RF have been observed in other autoimmune conditions such as Sjögren syndrome and systemic lupus erythematosus (SLE) as well as non-autoimmune conditions including old age and chronic infections. Despite this, RF in RA patients can be distinguished from RF in healthy individuals. RF in RA patients displays affinity maturation whereas RF in healthy individuals has low affinity and are polyreactive 2.
RF is a class of immunoglobulin (Ig) autoantibodies that are directed against the fragment crystallizable region (Fc region), the tail region of the IgG antibody. In RA, RF are produced by the B cells present in lymphoid follicles and the germinal center(GC)-like structures that mature in inflamed synovium. Most RF are IgM antibodies, but may also be IgG or IgA isoforms. IgM RF are detected in 60% to 80% of RA patients. “RF testing in RA patients has a sensitivity of 60% to 90% and a specificity of 85%” (5). RF is a highly valuable biomarker in RA 5, 2.
Key Features of the Randox Rheumatoid Factor Assay
The Randox automated latex enhanced immunoturbidimetric rheumatoid factor assay provides an accurate assessment of RF titre as the Randox rheumatoid factor calibrator is standardised against the primary WHO material, 1st British Standard 64/2. With a wide measuring range of 6.72 – 104lU/ml for the comfortable detection of clinically important results, the Randox RF assay is available in a liquid ready-to-use format for the comfortable detection of clinically important results. The Randox rheumatoid factor assay does not suffer from interference from C1q complement and is stable until expiry date. With dedicated calibrator and controls for a complete testing package, Randox offer applications, detailing instrument-specific settings for the convenient use of the Randox rheumatoid factor assay on a wide range of clinical chemistry analysers.
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Since 2012, September has been devoted to raising awareness of Alzheimer’s disease (AD) with Alzheimer’s Day on 21st September each year. Dementia is the medical name attributed to a set of symptoms affecting the brain, including: difficulties with problem solving, thinking, language and memory loss. AD is the most common form of dementia accounting for 60 – 80% of cases and it is believed that half of patients with Alzheimer’s dementia (dementia due to AD) have Alzheimer’s disease 1, 2.
About Alzheimer’s Disease (AD)
AD is one of the most devastating and complex diseases characterised by:
. Neurodegeneration resulting in memory loss 2
. Neurofibrillary tangles composed of tau amyloid fibrils which associates with synapse loss 2
. Accumulation of β-amyloid (Aβ) plaques 2
. Other cognitive functions 2
It is believed that AD is expected to begin 20 years prior to symptom onset, as the small changes in the functioning of the brain are unnoticeable to the person affected. Overtime, the symptoms progress and begin to interfere with the patient’s ability to perform everyday tasks. The final stages of AD leaves the patient bed-bound, requiring 24/7 care. Ultimately, AD is fatal. Age has been identified as a risk factor for AD with 10% of people over the age of 65 affected. Moreover, AD has been recognised as a leading cause of morbidity and the sixth leading cause of mortality, but the fifth leading cause of death in over 65’s in the US 3.
Figure 1: Alzheimer’s Disease Demographic, 2019 3
Physiological Significance of Apolipoprotein E
Apolipoprotein E (Apo E) is a lipoprotein composed of 299 amino acids with a molecular weight of 34kDa. Apo E is responsible for the regulation of homeostasis through the mediation of lipid transport from and to bodily cells and tissues. Apo E comprises of three common isoforms: apo E2, apo E3 and apo E4. The apo E isoforms differ due to differences in either the 112 and 158 amino acids, whether either arginine (ARG) or cysteine (CYS) is present 4.
Apo E3 is the parent form of apo E and is responsible for the clearance of triglyceride-rich lipoproteins. Apo E3 is associated with normal lipid plasma concentrations. Apo E2 is the rarest of the apo E isoforms and differs slightly compared to the apo E3 isoform through the substitution of a single amino acid, ARG158Cys, located near the low-density lipoprotein receptor (LDLR) recognition site. Apo E2 displays impaired binding to the receptor, prohibiting the clearance of triglyceride-rich lipoprotein remnant particles. Apo E2 is strongly associated with type-III hyperlipoproteinemia. Apo E3 also differs from apo E4, again through the substitution of a single amino acid, Cys112Arg. The main difference between apo E3 and apo E4 is that apo E4 is unaffected by the binding of the isoform to LDLR. However, apo E4 is strongly associated with dyslipidemia 5. Fig. 2 provides a visual representation of the variations in the Apo E isoforms.
Figure 2: Variations in the Apo E Isoforms 4
Apo E is expressed in numerous bodily organs with the liver presenting with the highest expression followed by the brain. Astrocytes and, to a lesser extent, microglia are the major cells responsible for the expression of apo E in the brain. In the brain, apo E, apo J and apo A-1 are predominantly expressed on distinct high-density-like lipoprotein particles. Whilst apo A-1 is the major apolipoprotein of high-density lipoproteins (HDL), in the central nervous system (CNS), apo E is the predominant apolipoprotein of HDL-like lipoproteins. HDL-like lipoproteins are the only lipoproteins present in the CNS. It is believed that the cholesterol released from apo E supports synaptogenesis 6.
Clinical Significance of Apolipoprotein E in Alzheimer’s Disease
Whilst apo E3 is the most abundant of the three isoforms, apo E4 has been known for decades to be the most significant genetic risk factor for late-onset AD. Inheriting the one copy of the apo E4 gene increases the risk of AD 2-3-fold, whilst inheriting two copies increases the risk of AD up to 12-fold 7. Whilst the underlying mechanism of apo E’s contribution to AD risk is still unclear and debatable, apo E has been identified as promoting amyloid β (Aβ) deposition and clearance as well as neurofibrillary tangles in the brain. Interestingly, Aβ-independent pathways exist for apo E in AD, which led to the unearthing of the new roles of apo E including the most recent, iron metabolism and mitochondria dysfunction 8, 9. Captivatingly, sex-related hormones may play a role in AD in apo E4 carriers as AD has been recognised to be more pronounced in women 10. Apo E4 has also been identified as impairing lipid transport, microglial responsiveness, glucose metabolism, synaptic plasticity and integrity, and cerebrovascular function and integrity. Some of these pathogeneses are independent of Aβ pathways. Furthermore, therapeutic strategies are aiming to modulate the quantity, lipidation, structural properties, Aβ interaction and receptor expression of Apo E 11.
Key Features of the Randox Apolipoprotein E Assay
Randox are one of the only manufacturers to offer the apo E assay in an automated clinical chemistry format. Utilising the immunoturbidimetric method, the Randox apo E assay is available in a liquid ready-to-use format. Not only does the Randox apo E suffer from limited interferences from bilirubin, haemoglobin, intralipid® and triglycerides for truly accurate results, it has an excellent measuring range of 1.04 – 12.3mg/dl for the comfortable detection of clinically important results. Moreover, apolipoprotein calibrator and controls are available for a complete testing package. Applications are available detailing instrument-specific settings for the convenient use of the Randox apo E assay on a wide range of clinical chemistry analysers.
Biochip Technology – Alzheimer’s Array
Utilising the Biochip Technology, Randox have developed an array to identify the risk of Alzheimer’s disease in just 3 hours with one effective test. In addition to a rapid and accurate diagnosis, this also introduces both cost and time-saving benefits. The apo E4 array is a research use only product developed for the Evidence Investigator, a semi-automated benchtop immunoassay analyser which can process up to 2376 test per hour as well as up to 44 analytes screened per biochip. The apo E4 array measures both total apo E protein levels and apo E4 protein levels directly from plasma samples as well as using a ratio, it can classify patients as negative or positive for apo E4. In turn, we can then assess their risk for the development of Alzheimer’s disease.
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 Alzheimer’s Society. Alzheimer’s disease. [Online] [Cited: September 2, 2019.] https://www.alzheimers.org.uk/about-dementia/types-dementia/alzheimers-disease.
 Gaugler, Joseph, et al. 2019 Alzheimer’s Disease Facts and Figures. s.l. : Alzheimer’s Association, 2019.
 2014 Update of the Alzheimer’s Disease Neuroimaging Initiative: A review of papers published since its inception. Weiner, Michael W, et al. 6, San Francisco : Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, 2015, Vol. 11.
 Apolipoprotein E and Alzheimer disease: risk, mechanisms, and therapy. Liu, Chia-Chen, et al. 2, Fujian : Nature Reviews Neurology, 2013, Vol. 9.
 Apolipoprotein E isoforms and lipoprotein metabolism. Phillips, Michael C. 9, Philadelphia : IUBMB Journals, 2014, Vol. 66.
 The Role of Apolipoprotein E in Alzheimer’s Disease. Kim, Jungsu, Basak, Jacob M and Holtzman, David M. 3, St Louis : Neuron, 2009, Vol. 63.
 Dacks, Penny. What ApoE Means For Your Health. Cognitive Vitality. [Online] November 16, 2016. [Cited: September 11, 2019.] https://www.alzdiscovery.org/cognitive-vitality/blog/what-apoe-means-for-your-health.
 The Complex Role of Apolipoprotein E in Alzheimer’s Disease: an Overview and Update. Mahoney-Sanchez, Laura, et al. 3, Parkville : Journal of Molecular Neuroscience, 2016, Vol. 60.
 Understanding the Role of ApoE Fragments in Alzheimer’s Disease. Muñoz, SS, Gerner, B and Ooi, L. 6, Wollongong : Neurochemical Research, 2019, Vol. 44.
 ApoE4: an emerging therapeutic target for Alzheimer’s disease. Affieh, Mirna, Korczyn, Amos D and Michaelson, Daniel M. 64, s.l. : BMC Medicine, 2019, Vol. 17.
 Apolipoprotein E and Alzheimer disease: pathobiology and targeting strategies. Yamazaki, Yu, et al. 9AB, s.l. : Nature Reviews Neurology, 2019, Vol. 15.
A new testing application for the biomarker Heart-Type Fatty Acid-Binding Protein (H-FABP) has been announced by global diagnostics company Randox Laboratories.
Whilst H-FABP is most commonly recognized as an early biomarker of myocardial infarction, the assay’s clinical utility in cardiac surgery associated acute kidney injury (CSA-AKI) is notable. Studies have shown that patients who developed AKI following cardiac surgery had elevated levels of H-FABP both pre-and postoperatively compared to the patients who did not.
Susan Hammond, Randox Product Specialist, explained the new application for H-FABP;
“Cardiac surgery-associated acute kidney injury (CSA-AKI) is a well-recognized postoperative complication of cardiac surgery and is the second most common cause of AKI in the intensive care unit (ICU) – occurring in up to 30% of patients.
“Several AKI studies exist focusing on the measurement of H-FABP levels before, during and after cardiac surgery, one of which found that the post-operative H-FABP levels in patients who experienced any AKI increased 8-fold. It was also noted that the levels of those with severe AKI increased 13-fold and that 10.8% of patients who died from subsequent AKI all had elevated pre-operative levels of H-FABP.
“The Randox H-FABP assay is therefore an independent marker of AKI following cardiac surgery, and can furthermore be used as a CSA-AKI risk assessment assay even in advance of the procedure.”
It has been identified that certain patient groups are more susceptible to CSA-AKI and vulnerability can depend on age, sex, pre-existing cardiac dysfunction, pre-existing chronic kidney disease (CKD), previous cardiac surgery or comorbidity.
Susan Hammond added;
“The ability to include biomarkers that aid in the risk assessment and treatment plan management of a patient is significant. Utilizing H-FABP alongside traditional biomarkers to assess CSI-AKI risk allows the clinician to gain stronger clinical insight in how to improve patient outcomes.”
Key Benefits of the Randox H-FABP assay
A niche product from Randox meaning that Randox are one of the only manufacturers to offer the H-FABP assay in an automated biochemistry format
CE marked for diagnostic use
Automated assay offering a more convenient and time efficient method for H-FABP measurements compared to traditional testing
Exceptional correlation of r=0.97 when compared against other commercially available methods
Applications available detailing instrument-specific settings for the convenient use of the Randox H-FABP assay on a wide range of clinical chemistry analysers
Liquid ready-to-use format for convenience and ease-of-use
Latex enhanced immunoturbidimetric method delivering high performance compared to traditional ELISA testing
Rapid results within fourteen minutes, depending on the analyser.
Wide measuring range of 0.747 – 120ng/ml for the early detection of clinically important results
Dedicated H-FABP controls and calibrator available offering a complete testing package
Global diagnostics company Randox Laboratories has unveiled an innovative new test for the risk assessment of cardiovascular disease at this year’s AACC Clinical Lab Expo in Anaheim, California. The test detects and measures the cardiac biomarker sPLA2-IIA. When raised, sPLA2-IIA is an independent indicator of primary and secondary cardiovascular risk. The release of the new automated sPLA2-IIA assay from Randox adds to the company’s extensive cardiac and lipid testing panel, that are all designed for use on biochemistry platforms.
Susan Hammond, Product Specialist, commented;
“By 2030, it is estimated that almost 23.6 million people globally will die from CVD, with heart disease and stroke projected to remain the leading causes of death. This confirms that early diagnosis is an essential step in reducing the number of individuals affected. The continued investment and addition of early biomarkers that add clinical utility in cardiac risk testing is key to refining clinical assessment, and ultimately the treatment plan required.”
sPLA2-llA, a member of the secretory phospholipase A2 family, offers clinical utility as an inflammatory biomarker specifically in the diagnosis of CVD risk. As the prototypic member of the group II sPLA2 subfamily, it is known as “inflammatory sPLA2”.
Susan Hammond continued;
“sPLA2 -llA hydrolyses phospholipids from membranes, native lipoproteins and oxidized protein. As it is not bound to Apolipoprotein B its impact is more significant. Hydrolysis produces biolipid mediators lyso phospholipids and fatty acids along with Arachidonic acid which then accelerates inflammatory mediators. Due to increases in lipid and inflammatory mediators, increased cholesterol rich foam cells form- adding to plaque formation. sPLA2-IIA reduces biomarkers such as HDL-C capacity to mediate cellular cholesterol efflux from these lipid loaded macrophages.”
Key Benefits of the Randox sPLA2-llA assay
A niche product from Randox meaning that Randox are one of the only manufacturers to provide the sPLA2-llA mass test in an automated biochemistry format.
Applications available detailing instrument-specific settings for the convenient use of the Randox sPLA2-llA assay on a wide range of clinical chemistry analysers.
Liquid ready-to-use reagents for convenience and ease-of-use.
Latex enhanced immunoturbidimetric method delivering high performance.
Dedicated controls and calibrators available offering a complete testing package.
Automated assay which removes the inconvenience and time consumption associated with traditional ELISA based testing.
For Research Use Only!
Bile acids are water-soluble, amphipathic end products of cholesterol metabolism and are involved in liver, biliary and intestinal diseases. They are formed in the liver and are absorbed in the small intestine before being excreted. The fundamental role of bile acids is to aid in the digestion and absorption of fats and fat-soluble vitamins in the small intestine.1
Intrahepatic Cholestasis of Pregnancy
Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder. It can be indicated by pruritus, jaundice, elevated total bile acids and/or serum transaminases and usually affects women during the second and third trimester of pregnancy.2,3
Intrahepatic Cholestasis of pregnancy or Obstetric Cholestasis is a condition that restricts the flow of bile through the gallbladder resulting in a build-up of bile acids in the liver.3 Due to the build-up, bile acids leak into the bloodstream where they are detected at concerning levels. It is an extremely serious complication of pregnancy that can lead to the increased risk of premature birth or even stillbirth, as such it is vital that women with the disease are monitored carefully.
In healthy pregnancies, there is very little increase in total bile acid levels although a slight increase is likely to be seen in the third trimester. Measurement of total bile acids in serum is thought to be the most suitable method of diagnosing and monitoring ICP.6
According to several reports total bile acid levels in ICP can reach as high as 100 times the upper limit of a normal pregnancy. It has been reported that a doubling in maternal serum bile acids, results in a 200% increased risk of stillbirth with total bile acids thought to trigger the onset of preterm labour. Additionally, bile acids can affect the foetal cardiovascular system as it has been found that there are often cardiac rhythm disturbances in the foetus due to the elevated bile acids in circulation.5
Although it is a rare condition, with only 0.3-0.5% of women likely to develop ICP, it can have extreme risks and so it is important to properly diagnose and monitor the condition.6 ICP increases the risk of meconium staining of the amniotic fluid and is reported to be a sign of foetal distress. This complication is found in 16-58% of all ICP cases, worryingly 100% of cases have resulted in foetal death. The frequency of this condition is found to be greater in pregnancies with higher levels of serum total bile acids.
There are several risk factors associated with ICP such as a family history of ICP, use of oral contraceptives, assisted reproduction techniques and multiple gestation. Genetic influence accounts for approximately 15% of ICP cases. Dietary selenium is a contributing environmental factor as serum selenium levels often decrease throughout pregnancy. Further to this, incidences of ICP rise in the winter months, most likely due to the fact selenium levels are naturally less during these months.7,8
Total Bile Acids
In addition to ICP, bile acid levels are also measured in the diagnosis of other liver disorders. The bile acids test in an extremely sensitive indicator of liver function, capable of detecting changes in hepatic function before clinical symptoms arise, thus providing valuable information that standard liver function tests cannot. As a result of its high sensitivity, bile acids can be used to assess liver function in transplant patients, allowing monitoring of the transplant success and of antirejection therapy. The bile acids test is most beneficial when used in conjunction with standard liver function tests such as ALT and AST which are markers of liver damage rather than liver function.
Measurement of Total Bile Acids
The enzyme cycling method, also known as the Fifth Generation Bile Acids test, is a method that allows for signal amplification through cycled regeneration reactions as can be seen in Figure 1. In the presence of Thio-NAD, the enzyme 3-α hydroxysteroid dehydrogenase (3-α HSD) converts bile acids to 3-keto steroids and Thio-NADH. The reaction is reversible and 3-α HSD can convert 3-keto steroids and Thio-NADH to bile acids and Thio-NAD. In the presence of excess NADH, the enzyme cycling occurs efficiently and the rate of formation of Thio-NADH is determined by measuring specific change of absorbance at 405 nm and is proportional to the amount of total bile acids in the sample. The analysing capability of the fifth generation total bile acids assay is far beyond the performance of conventional bile acid tests.10,11
Figure 1: The assay principle⁹
Inadequacies of Traditional Bile Acids Assays
Determining the cause and extent of liver damage is important in guiding treatment decisions and preventing disease progression. Standard liver function tests include; ALT, AST, ALP, GGT and Bilirubin. The measurement of TBA is most beneficial in conjunction with these standard liver tests and offers unrivalled sensitivity allowing identification of early stage liver dysfunction. There are several commercial methods available for the detection and measurement of TBA in serum. Traditional TBA tests based on the enzymatic method use nitrotetrazolium blue (NBT) to form a formazan dye. The reaction is measured at 546nm and the intensity of the colour is proportional to the concentration of bile acids.
Newer methods such as the enzyme cycling method or fifth generation methods offer many advantages including greater sensitivity, liquid reagents, small sample volumes and reduced instrument contamination from formazan dye. Additionally, the fifth generation assay does not suffer from interference from lipaemic or haemolytic samples. Both lipemia and haemolysis are common in new-borns and pregnant women, so this further supports that the fifth generation test is more sensitive for these sample types.12
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 The continuing importance of bile acids in liver and intestinal disease. A.f., Hofmann. 1999, Arch Intern Med, pp. 2647-2658.
 Diagnostic and Therapeutic Profiles of Serum Bile Acids in Women with Intrahepatic Cholestasis of Pregnancy – A Pseudo-Targeted Metabolomics Study. Cui, Yue. Xu, Biao. Zhang, Xiaoqing. He, Yifan. Shao, Yong. Ding, Min. s.l. : Clinica Chimica, 2018, Vol. 483.
 Randox Laboratories. Bile Acids Test for Obstetric Cholestasis – A serious complication of pregnancy. 2012.
 British Liver Trust (2019) Facts about Liver Disease, Available at: https://www.britishlivertrust.org.uk/about-us/media-centre/facts-about-liver-disease/ (Accessed: 18th June 2019).
 .Geenes, Victoria. Williamson, Catherine. 17, s.l. : World J Gastroenterol, 2009, Vol. 15.
 Howland, Genevieve. Cholestasis of Pregnancy: Why You Can’t Ditch the Itch. Mama Natural. [Online] December 22, 2018. [Cited: February 19, 2019.] https://www.mamanatural.com/cholestasis-of-pregnancy/.
 Bile Acid Levels and Risk of Adverse Perinatal Outcomes in Intrahepatic Cholestasis of Pregnancy: A Meta-Analysis. Cui, Donghua, et al.
 Intrahepatic Cholestasis of Pregnancy. Chivers, Sian. Williamson, Catherine. 7, 2018, Vol. 28.
 Masoud, N; Neill, S.H. Serum bile acids as a sensitive biological marker for evaluating hepatic effects of organic solvents. Available from URL: https://www.ncbi.nlm.nih.gov/pubmed/23885947 [Accessed 1 November 2018]
 Microassay of Serum Bile Acids by an Enzymatic Cycling Method. Komiyama, Y, et al. 10, s.l. : Chemical and Pharmaceutical Bulletin, 1982, Vol. 30.
 Evaluation of a Colorimetric Enzymatic Procedure for Determining the Total Bile Acids in the Blood. Agape, V, et al. 3, s.l. : Minerva Gastroenterologica e Dietologica, 1989, Vol. 35.
 Total Bile Acids Test & Clinical Diagnosis. Diazyme. 2019.
Diabetes Week is an annual week to raise awareness of diabetes. This year, the aim is to increase the public’s understanding of diabetes 1. Diabetes mellitus (DM) is a global epidemic, increasing at an alarming rate and burdening healthcare systems 2. DM is a life-long condition characterised by the body’s inability to produce / respond to insulin resulting in the abnormal metabolism of carbohydrates and elevated blood glucose levels.
Whilst it is important to increase the public’s understanding of DM, it is imperative that clinicians and physicians are aware of the different in vitro diagnostic tests to diagnose and monitor DM. Not only is this vital, but is also important that clinicians and physicians also understand the different methodologies available when choosing the diagnostic test.
It has been highlighted in numerous clinical studies that diabetic complications may be reduced through the long-term monitoring and tight control of blood glucose levels. Both fasting plasma glucose (FPG) and glycated haemoglobin A1c (HbA1c) tests are universally accepted as reliable measurements of diabetic control. However, studies have emerged highlighting the role of fructosamine in diabetes monitoring. Whilst HbA1c provides an index of glycaemia over 2 to 3 months, fructosamine provides this index over the course of 2 to 3 weeks, enabling closer monitoring of diabetic control 1.
Drawbacks of Traditional Diabetes Tests
The FPG test measures the level of blood sugars which is used to diagnose and monitor diabetes based on insulin function. The main drawback of this test is that a hormone called glucagon, produced in the pancreas, is triggered during prolonged fasting, signalling the liver to release glucose into the bloodstream. In diabetic conditions, either the body is unable to generate enough insulin or cannot appropriately respond to insulin. Consequently, FPG levels remain high 4.
In the 1980’s, HbA1c was incorporated into clinical practice as HbA1c levels correlated well with glycaemic control over a 2 to 3-month period. The main drawback of this test is that any condition that reduces the survival rate of erythrocytes such as haemolytic anaemia will falsely lower the HbA1c test results, regardless of the assay method utilised 5.
In a diabetic patient where blood glucose levels are abnormally elevated, the concentration levels of fructosamine also increase as fructosamine is formed by a non-enzymatic Maillard reaction between glucose and amino acid residues of proteins. During this glycation process, an intermediate labile Schiff base is produced which is converted to a more stable ketoamine (fructosamine) via an Amadori rearrangement 2.
Fructosamine has been identified as an early indicator of diabetic control compared to other markers such as HbA1c. Red blood cells live for approximately 120 days, HbA1c represents the average blood glucose levels for the previous 2 to 3 months. Conversely fructosamine has a shorter lifespan, about 14 to 21 days, reflecting average blood glucose levels from the previous 2 to 3 weeks. Due to the shorter time span of fructosamine, it is also used to evaluate the effectiveness of medication changes and to monitor the treatment of gestational diabetes. The test is also particularly useful in situations where HbA1c cannot be reliably measured e.g. haemolytic anaemia, thalassemia or with genetic haemoglobin variants 5.
Fructosamine Assay Methodology
The most commonly utilised method for fructosamine testing is the colorimetric method. Whilst widely available, automated and inexpensive, the main drawback is the lack of standardisation across the different fructosamine assays 4.
Randox, on the other hand, utilise an enzymatic method, offering improved specificity and reliability compared to conventional NBT-based methods. The Randox enzymatic method does not suffer from non-specific interferences unlike existing methods which can also be time consuming and difficult to automate.
The Randox fructosamine assay is also standardised to the highest level as the Randox fructosamine calibrator and control is assigned relative to human serum glycated with 14C-glucose, which directly reflects the nature of the patient sample.
With an excellent stability of 28 days on-board the analyser, the Randox fructosamine assay is developed in a liquid ready-to-use format for convenience and ease-of-use.
Randox offer fully automated applications detailing instrument-specific settings for the convenient use of the Randox fructosamine assay on a wide range of clinical chemistry analysers.
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 Diabetes UK. Diabetes Week. [Online] 2019. [Cited: May 31, 2019.] https://www.diabetes.org.uk/get_involved/diabetes-week.
 Gounden, Verena and Jialal, Ishwarlal. Fructosamine. [Online] January 23, 2019. [Cited: April 11, 2019.] https://www.ncbi.nlm.nih.gov/books/NBK470185/.
 World Health Organization (WHO). Diabetes. [Online] October 30, 2018. [Cited: May 2, 2019.] https://www.who.int/news-room/fact-sheets/detail/diabetes.
 Manzella, Debra. The Fasting Plasma Glucose Test. very well health. [Online] November 16, 2018. [Cited: April 11, 2019.] https://www.verywellhealth.com/understanding-the-fasting-plasma-glucose-test-1087680.
 BMJ. Using haemoglobin A1c to diagnose type 2 diabetes or to identify people at high risk of diabetes. [Online] 2014. [Cited: April 11, 2019.] https://www.bmj.com/content/348/bmj.g2867/rr/695927.
The month of May is devoted to myositis awareness, a muscle-wasting disease resulting in reduced muscle strength and fatigue. The term ‘myositis’ is an umbrella term referring to the “general inflammation or swelling of the muscle”. However, myositis is more often referred to as a disease involving chronic inflammation of the muscles which does not improve with rest. This condition is also known as idiopathic inflammatory myopathy (IIM) 1.
Myositis is an autoimmune disease characterised by pain, muscle weaknesses, swelling and extreme fatigue which often gradually appear. Myositis can be potentially life-threatening, especially dermatomyositis which affects the heart muscle and lungs. Whilst a rare disease, it is estimated that 75,000 Americans suffer from myositis, however, many are undiagnosed or misdiagnosed with more common autoimmune diseases. Most physicians are unfamiliar with the disease and symptoms and so the consequences of this can be catastrophic in terms of long-term physical muscle damage, disability and even death 1, 2, 3.
Table 1 reviews the different forms of myositis
Table 2 reviews complications with or due to myositis
It is vital that physicians are educated to include myositis despite it being a rare disease as it is essential that myositis patients are diagnosed quickly to ensure appropriate treatment plans are implemented.
Aldolase testing has been recognised as a marker in the differential diagnosis of muscle weakness as aldolase levels remain consistent where weakness is caused by neurological problems such as multiple sclerosis (MS). Aldolase is an enzyme specifically found in skeletal muscle and the liver. When either the muscle or liver are damaged, aldolase is released into the bloodstream 13 . A few studies support aldolase testing in the diagnosis of myositis:
1. Arthritis Research & Therapy (2012): Aldolase predicts subsequent myopathy occurrence in systemic sclerosis 14
A French monocentric 4-year study prospectively evaluated n=137 systemic sclerosis (SSc) patients without proximal muscle weakness to assess the risk of myopathy related systemic sclerosis (Myo-SSc) according to the European Neuro Muscular Centre criteria. Aldolase, creatine kinase (CK), C-reactive protein (CRP), alanine transaminase (ALT) and aspartate transaminase (AST) were evaluated.
Aldolase is a valuable diagnostic tool in the identification of SSc patients at a high risk of developing subsequent Myo-SSc. This enables clinicians to monitor at-risk patients as well as identifying Myo-SSc in its earliest stages, enabling the effective and swift implementation of an appropriate treatment plan when the muscle damage is still in a reversible stage.
2. Clinical and Experimental Rheumatology (2013): Isolated elevation of aldolase in the serum of myositis patients: a potential biomarker of damaged early regenerating muscle cells 15
The in vitro analysis of the gene and protein expression levels of aldolase and CK during muscle cell differentiation.
Aldolase A is expressed in the absence of CK in undifferentiated muscle cells and in the early differentiation process. Isolated elevated serum aldolase A in myositis patients reflects preferential immune-mediated damage of early regenerative cells. Aldolase is a biomarker of damaged early regenerating muscle cells.
Myositis can be a potentially life-threatening disease when undiagnosed or misdiagnosed. Aldolase is recognised as a biomarker in the diagnosis and monitoring of myositis. Randox are one of the only in-vitro diagnostic manufacturers to offer the aldolase assay in an automated and manual biochemistry format. Not only does the Randox methodology have an excellent correlation coefficient to r=0.9917 when compared against standard methods, the Randox assay is lyophilised for enhanced stability with an excellent measuring range of 1.73 – 106U/l. Moreover, applications are available detailing instrument-specific settings for the convenient use of the Randox aldolase assay on a wide range of clinical chemistry analysers.
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Clinical Chemistry Panel
 The Myositis Association. About Myositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/.
 Kobert, Linda. Myositis, a rare muscular inflammatory disease that ofen goes undiagnosed or misdiagnosed, disproportionally impacts women of color. s.l. : The Myositis Organisation.
 Muscular Dystophy UK. Myositis. [Online] [Cited: May 6, 2019.] https://www.musculardystrophyuk.org/about-muscle-wasting-conditions/myositis/.
 The Myositis Association. Types of Myositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/types-of-myositis/.
 —. Sporadic Inclusion Body Myositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/types-of-myositis/sporadic-inclusion-body-myositis/.
 —. Dermatomyositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/types-of-myositis/dermatomyositis/.
 —. Polymyositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/types-of-myositis/polymyositis/.
 —. Necrotizing Myopathy. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/types-of-myositis/necrotizing-myopathy/.
 —. Juvenile Myositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/types-of-myositis/juvenile-myositis/.
 —. Cancer-associated myositis. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/complications/cancer-associated-myositis/.
 —. Infection. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/complications/infection/.
 —. Cardiovascular Disease. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/complications/cardiovascular-disease/.
 —. Blood Tests. [Online] [Cited: May 3, 2019.] https://www.myositis.org/about-myositis/diagnosis/blood-tests/.
 Aldolase predicts subsequent myopathy occurrrence in systemic sclerosis. Tolédano, Cécile, et al. Faubourg Saint-Antoine : Arthritis Research & Therapy, 2012.
 Isolated elevation of aldolase in the serum of myositis patients: a potential biomarker of damaged early regenerating muscle cells. Casciola-Rosen, Livia, et al. Baltimore : Clinical and Experimental Rheumatology, 2013.
To date, the most traditional diagnostic test for renal impairment is creatinine. However, although most commonly used, problems can arise when implementing this test as a number of factors are not considered. On this World Kidney Day, Randox will explore the potential utility of H-FABP as a clinical diagnostic marker for cardiac surgery-associated acute kidney injury.
Acute Kidney Injury (AKI) is defined as an acute decline in renal function that can lead to structural changes. It involves a sudden drop in kidney function that usually arises due to a complication of another serious illness such as impaired renal perfusion, exposure to nephrotoxins, outflow obstruction or intrinsic renal disease. As a result, a patient can experience effects such as impaired clearance and regulation of homeostasis, altered acid/base and electrolyte regulation and impaired volume regulation.1
The mortality rate associated with AKI varies depending on severity, patient related factors and setting including whether the patient is in intensive care (ICU) or not.2 In the UK, AKI has been found to affect 1 in 5 people admitted to hospital as an emergency and has been found to be deadlier than a heart attack, contributing to around 100,000 deaths each year. Conversely, in the US, age-standardized rates of acute kidney injury hospitalisations increased by 139% among adults with diagnosed diabetes and by 230% among those without diabetes.3, 4
The rising incidence of AKI comes at price. Patients tend to survive ICU but will be discharged with various degrees of chronic kidney disease (CKD), placing an increasing strain on the health care system. At present, the cost to the NHS is estimated to be between £434 and £620 million, which is more than the costs associated with breast cancer, or lung and skin cancer combined. However, this increased cost and strain could be unnecessary, as research has shown that 30% of the reported 100,000 deaths in the UK could have been prevented with the right care and treatment.3,4
These unfavourable statistics are the result of late detection of AKI, as to date, a superior method of detection has not been found.
Cardiac surgery-associated acute kidney injury (CSA-AKI)
CSA-AKI is a well-recognised postoperative complication of cardiac surgery and is the second most common cause of AKI in the intensive care unit, occurring in up to 30% of patients.5,6 Of these patients, an estimated 1% will require dialysis and the majority will remain dependent on dialysis leading to an increase in mortality. Certain patient groups are more susceptible to CSA-AKI and vulnerability can depend on age, sex, pre-existing cardiac dysfunction, pre-existing CKD, previous cardiac surgery or comorbidity.7
The pathogenesis of AKI involves multiple pathways including hemodynamic, inflammatory and nephrotoxic factors that overlap leading to kidney injury.6 Figure 1 illustrates the pathophysiology of AKI following cardiac surgery. It shows that there are multiple physiological processes that are associated with the development of AKI as a result of cardiac surgery.8
Figure 1 Illustrates the pathophysiology of AKI following cardiac surgery and the various mechanisms that contribute.8
What is H-FABP?
Fatty acid-binding proteins (FABPs) are small cytoplasmic proteins that are abundantly expressed in tissues with an active fatty acid metabolism, with their primary function being the facilitation of intracellular long-chain fatty acid transport.9 Elevated FABP serum concentrations are related to a number of common comorbidities including heart failure, CKD, diabetes mellitus and metabolic syndrome, which represent important risk factors for postoperative AKI.10
H-FABP is most commonly associated with being a marker for acute coronary syndrome (ACS) as its concentrations peak at approximately 6-8 hours after symptom onset, making it easier to detect. Recently studies have highlighted H-FABP as a potential biomarker for the detection of AKI after cardiac surgery. This potential would mean earlier diagnosis of patients, reducing the mortality rate and costs to the health service.
Potential Mechanism for the release of H-FABP in AKI
There are a number of hypotheses regarding the release of H-FABP, with myocardial injury being considered the major reason for an increased level. The mechanisms involved in this increase have been found to differ depending on the severity of a patients ACS situation including whether they are in ICU.11
One possible explanation for the release of H-FABP is the effects of ischemic stress. Ischemic stress induced by non-cardiogenic shock is a type of mechanical stretching which can lead to the leakage of small amounts of macromolecules. This process would lead to the release of H-FABP into the blood. In non-cardiac patients, minor myocardial injury alone may not adequately explain this observed increase. Other factors such as a reduction in the amount of skeletal muscle tissue, lipid disorders, release of free radicals and an increase in free acids produced by the catabolism of glycogen could also contribute to a rise in H-FABP levels.11
One final process that could lead to increased H-FABP is the damage of vital organ functions which occurs in almost all non-surgical intensive care patients. The degree of leakage of H-FABP may vary depending on the severity of a patient’s condition and whether they have suffered from multiple organ failure or vital organ damage. AKI is a component of multiple organ failure suggesting that serum H-FABP levels may increase in AKI patients as a result. Also, serum H-FABP is excreted by renal tubular cells and patients with an acutely diminished renal function are unable to clear large amounts of H-FABP resulting in increasing levels. These potential mechanisms of H-FABP and its release during AKI provide further confirmation that the measurement of serum H-FABP is an effective biomarker in patients with AKI.11
Comparison of H-FABP Measurement Against Traditional Acute Kidney Disease Measurement Tools
For years, no standard method for definition or diagnosis was in place for AKI. The RIFLE classification was introduced in 2004, which defined and staged renal failure over seven days into five classes of increasing severity including; risk, injury, failure, loss and end-stage kidney disease.
The RIFLE criteria were then revised by the Acute Kidney Injury Network (AKIN) and introduced four main changes including replacing the period of seven days for serum creatinine (SCr) with forty eight hours and implementing SCr changes as low as 0.3 mg/dL as the lowest measure considered as AKI. However, despite these changes the Kidney Disease Improving Global Outcome (KDIGO) proposed that AKI is defined when any of the three criteria are met including increase in SCr by 50% in seven days, increase in SCr > 0.3 mg/dL or oliguria.7
However, despite these advances, identification and management of AKI is still difficult for two main reasons. The change of SCr does not occur until two to three days after the initial insult. Also, serum creatinine can rise for a variety of reasons such as tubular injury, hemodynamic alterations or cardio-renal interactions.
The utility of SCr as biomarker for CSA- AKI is questionable as changes occur 48 hours to seven days after the original insult.5 The delays in diagnosis of CSA-AKI may have detrimental effects as prolonging the diagnosis period may result in the disease already being well established.12
Also, a main issue concerning the AKI criteria established is its relevance to the perioperative period. Many surgical patients arrive in hospital without preoperative SCr concentrations being measured, potentially leading to over-diagnosis of AKI. However, when patients do arrive with a preoperative SCr concentration, the opposite can occur and immediate postoperative period SCr concentrations can be lower than baseline as a result of haemodilution. A comparison of the postoperative and preoperative values can lead to under-diagnosis of AKI and consequently delayed treatment.12
The research conducted has illustrated that SCr is not the most appropriate biomarker for diagnosis of AKI. Studies have demonstrated that H-FABP has more clinical utility and is released less than thirty minutes after myocardial injury and renally excreted within 24 hours, showing that as a biomarker it responds faster than creatinine.12
How Randox can Help
The Randox H-FABP test tests utilises an immunoturbidimetric method, offers a wide measuring range and is available liquid ready-to-use for convenience and ease of use.
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Contact us or visit the Randox H-FABP Site
- National Kidney Foundation. Acute Kidney Injury (AKI). National Kidney Foundation. [Online] National Kidney Foundation. [Cited: February 3, 2019.] https://www.kidney.org/atoz/content/AcuteKidneyInjury.
- Biomarkers for the prediction of acute kidney injury: a narrative review on current status and future challenges. Geus, de, MG, Betjes and J , Bakker. 2, s.l. : NCBI, 2012, Vol. 5.
- Kidney Care UK. A range of useful facts and stats about kidneys. Kidney Care UK. [Online] Kidney Care UK. [Cited: February 15, 2019.] https://www.kidneycareuk.org/news-and-campaigns/facts-and-stats/.
- Centers for Disease Control and Prevention. Trends in Hospitalizations for Acute Kidney Injury — United States, 2000–2014. Centers for Disease Control and Prevention. [Online] Centers for Disease Control and Prevention, March 16, 2018. [Cited: February 22, 2019.] https://www.cdc.gov/mmwr/volumes/67/wr/mm6710a2.htm.
- Cardiac Surgery-Associated Acute Kidney Injury. Mao, h, et al. s.l. : Karger, 2013, Vol. 3.
- Acute Kidney Injury Associated with Cardiac Surgery. Rosner, Mitchell and Okusa, Mark. 1, s.l. : Clinical Journal of American Society of Nephrology, 2016, Vol. 1.
- Cardiac surgery-associated acute kidney injury. Loubon, Christian, et al. 4, s.l. : NCBI, 2016, Vol. 19.
- Acute kidney injury following cardiac surgery: current understanding and future directions. O’Neal, Jason, Shaw, Andrew and Billings, Frederic. s.l. : NCBI, 2016, Vol. 20.
- Heart-type fatty acid-binding protein predicts long-term mortality after acute coronary syndrome and identifieshigh-risk patients across the range of troponin values. Kilcullen, N, et al. 20, s.l. : Epub, 2012, Vol. 50.
- Preoperative serum h-FABP concentration is associated with postoperative incidence of acute kidney injury in patients undergoing cardiac surgery. Oezkur, Mehmet, et al. 117, s.l. : BMC Cardiovascular Disorders, 2014, Vol. 14.
- The serum heart-type fatty acid-binding protein (HFABP) levels can be used to detect the presence of acute kidney injury on admission in patients admitted to the non-surgical intensive care unit. Shirakabe, A, et al. 1, s.l. : NCBI, 2016, Vol. 16.
- Perioperative acute kidney injury. Goren, O and Matot, I. 2, s.l. : British Journal of Anaesthesia, 2015, Vol. 115.
Rare Disease Day raises awareness of rare diseases and how patients’ lives are affected. Many rare diseases remain incurable and many go undiagnosed. 1 in 20 people will live with a rare disease at some point in their life and this is why it is so important to raise awareness.1
What is a rare disease?
There is no single definition for a rare disease, as many countries identify them differently. In the United States, the Rare Diseases Act of 2002 defines a rare disease by its prevalence: “any disease or condition that affects fewer than 200,000 people in the United States”. However, the EU defines a rare disease as a condition that affects less than 5 in 10,000 of the population. There are approximately 7000 rare diseases and disorders and 50% of people affected by rare diseases are children.2,3
Hyperlipoproteinemia type III
This rare disease day, Randox will be raising awareness of hyperlipoproteinemia type III. Hyperlipoproteinemia type III, also known as dysbetalipoproteinemia or broad beta disease, is a rare genetic disorder characterised by improper breakdown of lipids, specifically cholesterol and triglycerides. The condition is caused by mutations in the Apo-E gene, however the inheritance of this condition is complicated due to the development of symptoms having to be triggered by a secondary factor to raise lipid levels. These factors include diabetes, obesity or hypothyroidism.
It is unknown exactly what the prevalence of the condition is, but it is estimated to affect approximately 1 in 5,000 – 10,000 of the general population and it has been found that it affects males more often than females, with women rarely being affected until after menopause.4,5
Figure A. Example of cholesterol and lipid build-up 
Symptoms for hyperlipoproteinemia type III will vary for each individual and some people may even be asymptomatic. The most common symptom is the development of xanthomas which are deposits of fatty material, the lipids, in the skin and underlying tissue. Xanthomas may appear on the palms of the hands, eyelids, soles of the feet or on the tendons of the knees and elbows.
> Chest pain or other signs of coronary artery disease
> Cramps in the calves when walking
> Sores on toes
> Stroke-like symptoms such as trouble speaking, dropping on one side of the face, weakness in an arm or a leg and a loss of balance6
Complications can arise if the condition is left untreated and these can include: myocardial infarction, ischemic stroke, peripheral vascular disease, intermittent claudication and gangrene of the lower extremities.7
Although there is no specific diagnostic test for hyperlipoproteinemia type III, diagnosis is based on clinical evaluation and identification of symptoms. Research has indicated that an algorithm comprising a number of dysbetalipoproteinemia indices may be helpful in the diagnosis of the disease. These include:
> Low apolipoprotein B to total cholesterol ratio
> Elevated levels of triglycerides
> Elevated levels of total cholesterol8
Managing the condition
The condition cannot be cured but treatment is to control conditions such as obesity, hypothyroidism and diabetes. Most patients will go through dietary therapy to control their intake of cholesterol and saturated fat. This prevents xanthomas, high levels of lipids in the blood, exercise will also help to lower lipid levels. However, dietary changes may not be effective for some individuals and this is where drugs may be used to lower lipid levels instead.
How Randox can Help
Randox offer a range of routine and niche assays within the lipid testing panel to monitor lipid levels and to identify associated complications. Some of these tests include:
The Randox Apolipoprotein B tests utilises an immunoturbidimetric method, offers a wide measuring range and is available liquid ready-to-use for convenience and ease of use.
The Randox Total Cholesterol test utilises the CHOD-PAP method and offers an extensive measuring range with a wide range of kits available to suit a wide range of laboratory sizes.
The Randox Triglycerides test utilises the GPO-PAP method while offering an extensive measuring range with both liquid and lyophilised formats available offering choice and flexibility.
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Lipid Panel Page
 Rare Disease Day. What is Rare Disease Day? Rare Disease Day. [Online] 2019. [Cited: February 21, 2019.] https://www.rarediseaseday.org/article/what-is-rare-disease-day
 Genetic Alliance UK. What is a Rare Disease? Rare Disease UK. [Online] 2018. [Cited: February 21, 2019.] https://www.raredisease.org.uk/what-is-a-rare-disease/
 NZORD. Rare Disease Facts and Figures. NZORD. [Online] 2019. [Cited: February 21, 2019.] https://www.nzord.org.nz/helpful-information/rare-disease-facts-and-figures.
 NORD. Hyperlipoproteinemia Type III. NORD. [Online] 2019. [Cited: February 21, 2019.] https://rarediseases.org/rare-diseases/hyperlipoproteinemia-type-iii/
 GARD. Hyperlipidemia Type 3. National Centre for Advanciing Translational Sciences. [Online] December 29, 2016. [Cited: February 21, 2019.] https://rarediseases.info.nih.gov/diseases/6703/hyperlipidemia-type-3
 Falck, Suzanne. Everything you need to know about hyperlipidemia. Medical News Today. [Online] December 21, 2017. [Cited: February 21, 2019.] https://www.medicalnewstoday.com/articles/295385.php
 Medline Plus. Familial Dysbetalipoproteinemia. Medline Plus. [Online] May 16, 2018. [Cited: February 21, 2019.] https://medlineplus.gov/ency/article/000402.htm.
 Dysbetalipoproteinemia: Two cases report and a diagnostic algorithm. Kei, Anastazia, et al. 4, s.l. : World Journal of Clinical Cases, 2015, Vol. 3.
The month of January has forever been the month of resolutions with many choosing to ditch the sweets and join the gym. However, for many these efforts are limited to January and bad habits are quick to remerge. Obesity has been a burden on the health service for many years with the problem, like many people’s waist lines, only continuing to expand.
Recent findings have shown that this problem is no longer just increasing in developed countries but also in developing countries. In fact, worldwide obesity has tripled since 1975. In 2016, more than 1.9 million adults were classed as overweight, of which over 650 million were obese.1 These are shocking statistics for a condition that is preventable. As a global concern, it is important to assess all the potential risks of this problem.
The most common diseases associated with obesity are cardiovascular disease (CVD) and diabetes. However, the associated risks are much greater than this. Being overweight may also increase the risk of certain types of cancer, sleep apnea, osteoarthritis, fatty liver disease and kidney disease.2
Obesity is now recognised as a potent risk factor for the development of renal disease.3 Excess weight has a direct impact on the development and progression of chronic kidney disease (CKD). Globally, the prevalence of diabetic kidney disease rose by 39.5% between 2005 and 2015, coinciding with the increased CKD prevalence.4 In obese individuals, the kidneys have to work harder, filtering more blood than normal to meet the metabolic demands of increased body weight, increasing the risk of kidney disease.
The traditional diagnostic test for renal impairment is creatinine. This test is carried out through the measurement of creatinine levels in the blood to assess the kidneys ability to clear creatinine from the body. This is called the creatinine clearance rate which helps to estimate the glomerular filtration rate (GFR), which is the rate of blood flow through the kidneys.5
Problems arise when using creatinine for CKD testing as a number of factors need to be taken into consideration including age, gender, ethnicity and muscle mass. For this reason, black men and women exhibit higher creatinine levels than white men and women, raising concern over the accuracy of this test for certain patient groups.6 In addition, serum creatinine is not an adequate screening test for renal impairment in the elderly due to their decreased muscle mass.7
The main disadvantage of using creatinine to screen for renal impairment is that up to 50% of renal function can be lost before significant creatinine levels become detectable as creatinine is insensitive to small changes in GFR. Consequently, treatment is not provided at the appropriate time which can be fatal, therefore, an earlier and more sensitive marker for renal function is vital.8
These disadvantages have not only been highlighted in research but also by the national institute for health and care excellence (NICE). NICE updated the classification of CKD in 2004 to include the albumin: creatinine ratio (ACR). They split chronic kidney disease patients into categories based on GFR and ACR. Figure 1 highlights the different categories and risk of adverse outcomes. NICE recommend using eGFR Cystatin C for people in the CKD G3aA1 and higher.9
Figure 1 Classification of Chronic Kidney Disease using GFR and ACR categories.9
Despite these suggestions, Creatinine is still being used for G3a1 and increasing risk levels.
The utility of cystatin C as a diagnostic biomarker for kidney disease has been documented to show superiority of traditional CKD tests. There is no ‘blind area’ making it very sensitive to small changes in GFR and capable of detecting early reductions. Furthermore, this marker is less influenced by diet or muscle mass and has proven to be a beneficial test in patients who are overweight.8
A number of studies support the statement: ‘Cystatin C levels are higher in overweight and obese patients’. This is important because when cystatin c levels are too high, it may suggest that the kidneys are not functioning properly. One study conducted, using a nationally representative sample of participants, found that overweight and obesity maintained a strong association with elevated serum cystatin C. This suggests that weight can affect the levels of cystatin C and therefore the likelihood of developing kidney disease.10
How Randox can Help
The Randox automated Latex Enhanced Immunoturbidimetric Cystatin C tests offers an improved method for assessing CKD risk, combined with a convenient format for routine clinical use, for the early assessment of at risk patients. Randox is currently one of the only diagnostic manufacturers who offer an automated biochemistry test for Cystatin C measurement, worldwide.
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- World Health Organization. Obesity and Overweight . int. [Online] WHO. [Cited: January 22, 2019.] https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight.
- Health Risks of Being Overweight. NIDDK. [Online] National Institute of Diabetes and Digestive and Kidney Diseases. [Cited: March 24, 2019.] https://www.niddk.nih.gov/health-information/weight-management/health-risks-overweight.
- Kidney Health Australia . Obesity and Chronic Kidney Disease: The Hidden Impact. Kidney Health Week/ World Kidney Day 2017. [Online] Kidney Health Australia. [Cited: January 22, 2019.] https://kidney.org.au/cms_uploads/docs/kidney-health-australia-report-obesity-and-chronic-kidney-disease–the-hidden-impact_06.03.17.pdf.
- Neuen, Brendon Lange, et al. Chronic kidney disease and the global NCDs agenda. s.l. : BMJ Global Health, 2017
- Creatinine and Creatinine Clearance Blood Tests. WebMD. [Online] WebMD. [Cited: January 22, 2019.] https://www.webmd.com/a-to-z-guides/creatinine-and-creatinine-clearance-blood-tests#1.
- Lascano, Martin E and Poggio, Emilio D. Kidney Function Assessment by Creatinine-Based Estimation Equations. Cleveland Clinic. [Online] August 2010. [Cited: 16 May 2018.] http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/nephrology/kidneyfunction/.
- Swedko, Peter J, et al. Serum Creatinine Is an Inadequate Screening Test for Renal Failure in Elderly Patients. Research Gate. [Online] February 2003. [Cited: 6 May 2018.] https://www.researchgate.net/publication/8243393_Serum_Creatinine_Is_an_Inadequate_ Screening_Test_for_Renal_Failure_in_Elderly_Patients.
- Mishra, Umashankar. New technique developed to detect chronic kidney disease. Business Line. [Online] 07 May 2018. [Cited: 17 May 2018.] https://www.thehindubusinessline.com/news/science/new-technique-to-detect-chronic-kidney-disease/article23803316.ece.
- National Institute for Health and Care Excellence. Chronic kidney disease in adults: assessment and management: 1 Recommendations. National Institute for Health and Care Excellence. [Online] January 2015. https://www.nice.org.uk/guidance/cg182/chapter/1- recommendations#classification-of-chronic-kidney-disease-2.
- Overweight and Obesity and Elevated Serum Cystatin C Levels in US Adults . Muntner, Paul, et al. 4, s.l. : NCBI, 2008, Vol. 121.