Molecular QC and EQA for Infectious Disease Testing
Earlier this year, Randox entered into a strategic partnership, bringing on-board Qnostics Molecular Controls and QCMD Molecular EQA which comprises hundreds of controls and EQA programmes for molecular infectious disease testing.
The Global Molecular Diagnostics market is estimated to be worth 6.54 billion USD. This market is classified into infectious diseases, oncology, genetic tests and blood screening. Infectious diseases account for the largest share of the global market.
According to the World Health Organisation (WHO), Infectious Diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi. These diseases can be spread – directly or indirectly – from one person to another.
Designed to meet the demands of today’s molecular diagnostics laboratory and laboratories carrying out Nucleic Acid Testing (NAT), the Qnostics range comprises hundreds of characterised viral, bacterial and fungal targets covering a wide range of Transplant Associated Diseased, Respiratory Diseases, Blood Borne Viruses, Sexually Transmitted Infections, Gastro-Intestinal Diseases and Central Nervous System Diseases.
Qnostics products can be used in the daily monitoring of assay performance, linearity assessment, assay evaluation, validation/verification of new assays and staff training.
There are five main product areas for Qnostics:
Product Groups (click to expand)
Q Controls
Independently manufactured, this range of positive run, whole pathogen, third party controls are designed to monitor the daily performance of a wide of range molecular assays used in the detection of infectious diseases. These controls help in supporting a laboratory’s accreditation requirements, in line with ISO 15189:2012.Analytical Q Panels
Designed to cover the dynamic range of an assay, Analytical Q Panels allow assessment of an assays linearity, LOD and LOQ. Each panel contains a minimum of five samples, including a negative that spans the dynamic range of the assay in a linear progression.Molecular Q Panels
Consisting of three levels (high, medium and low), Molecular Q Panels are intended to evaluate an assays analytical measuring range. Molecular Q Panels can also be used to support training of laboratory staff and in the development of molecular diagnostic assays.Evaluation Panels
Evaluation Panels cover a range of genotypes and may be used to evaluate assay characteristics, confirm performance claims and ultimately ensure the assay is fit for purpose. Evaluation Panels may also be used in the validation of molecular assays and development of new molecular diagnostic assays.QCMD Past Panels
Available for use in assay evaluation and staff training, EQA samples are available from past QCMD challenges.Custom ManufactureQnostics are specialists in the custom manufacture of quality control materials for use in the detection of infectious diseases using molecular based methods. Qnostics will work with you to develop a bespoke solution designed specifically to meet the individual and unique requirements of your lab.
- Choose from hundreds of molecular characterised targets
- Targets can be custom made into numerous different formats
- The whole pathogen format accurately mimics clinical samples
- All materials can be provided in a “ready-to-use” or liquid frozen format
Qnostics custom made Molecular Infectious Disease Controls are designed to fit all stages of your assays product life cycle from product development to launch.
QCMD is a world leading External Quality Assessment (EQA) / Proficiency Testing (PT) scheme, dedicated to improving the quality of molecular diagnostic assays used in the detection of infectious diseases.
With an extensive database of over 2000 participants in over 100 countries, QCMD is one of the largest providers of molecular EQA in the field of infectious disease testing.
EQA participants receive an individual report outlining their performance relative to their method and technology groups. A supplementary report may be commissioned – this includes any additional relevant information regarding the annual EQA distribution, as well as scientific expert commentary and feedback on the overall results within that distribution.
Features & Benefits (click to expand)
Frequency
A variety of programme options are available. Choose the number of challenges that best suit your laboratory’s requirements.
Online EQA Management System
ITEMS provides an online tool to easily manage all EQA activities from programme registration to submission of results and provision of EQA reports. Different levels of user access are available so data can be accessed by whoever needs it.
High level of participation
Over 2000 participants in more than 100 countries ensuring peer group numbers are maximised.
Comprehensive reports
Receive individual reports for each challenge and a final supplementary report at the end of the cycle visual assessment of performance.
International accreditation
Programmes are accredited to ISO 17043.
Qnostics
QCMD
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Product Spotlight: Acusera Immunoassay Premium Plus Control
The Randox Acusera Immunoassay Premium Plus quality control covers an impressive 54 analytes with assayed instrument specific target values and ranges provided for up to 51 analytes. The unique combination of routine tumour markers, therapeutic drugs and Vitamin D allows laboratories to dramatically reduce the number of controls required while ultimately keeping costs to a minimum. Three levels of control are available with analytes present at clinically significant levels.
Features & Benefits
- Lyophilised for enhanced stability
- 100% human serum
- Assayed, instrument specific target values provided for up to 51 parameters
- Ferritin and Vitamin B12 levels suitable for anaemia monitoring
- Ultra low TSH levels in the level 1 control
- Stable to expiry date at 2°C – 8°C
- Reconstituted stability of 7 days at 2°C – 8°C or 4 weeks at -20°C
- Contains routinely run tumour markers: AFP/CA15-3/CA19-9/CA-125/CEA/PSA/Free-PSA
Flexible options are available with a low, normal and high level, as well as a combined tri-level.
Description |
Size |
Analytes |
Cat No. |
| Immunoassay Premium Plus Level 1 | 12 x 5 ml | 54 | IA3109 |
| Immunoassay Premium Plus Level 2 | 12 x 5 ml | 54 | IA3110 |
| Immunoassay Premium Plus Level 3 | 12 x 5 ml | 54 | IA3111 |
| Immunoassay Premium Plus Tri-Level | 4 x 3 x 5 ml | 54 | IA3112 |
The clinical significance of some selected analytes.
Androstenedione
Androstenedione is an androgen, which are hormones responsible for the induction of sexual differentiation and produce secondary male physical characteristics such as a deep voice and facial hair. Another example is testosterone. They are also present in females as precursors to female hormones (such as estrogen).
This test measures the amount of androstenedione in the blood. Because AD has its origins in the adrenal glands, it is useful as a marker of adrenal gland function, of the function of the ovaries or testicles, and androgen production.
An androstenedione level may be used to [1]:
• Evaluate adrenal gland function and distinguish between androgen-secreting conditions that are caused by the adrenal glands from those that originate in the ovaries or testicles, if results of DHEAS and testosterone testing are abnormal • Help diagnose tumours in the outer layer (cortex) of the adrenal gland or tumours outside of the adrenal gland that secrete ACTH (ectopic) and separate these conditions from ovarian or testicular tumours and cancers • Diagnose congenital adrenal hyperplasia (CAH) and monitor CAH treatment, in addition to tests for testosterone and 17-hydroxyprogesterone • Help diagnose polycystic ovarian syndrome (PCOS) and help rule out other causes of infertility, no monthly menstrual periods (amenorrhea), and excess body and facial hair (hirsutism) in women who have abnormal results on tests for DHEAS, testosterone, and other hormones such as FSH, LH, prolactin, and estrogen • Help determine the cause of delayed puberty and investigate suspected ovarian or testicular failure • Investigate and diagnose the cause of male physical characteristics (virilisation) in young girls and early (precocious) puberty in young boys Digoxin
Digoxin is a therapeutic drug used to treat abnormal heart rhythms and failure. Heart failure causes the heart to become less effective at circulating blood, resulting in blood backing up in the hands, legs, liver, and lungs, causing swelling.
This test measures the level of digoxin in the blood. Digoxin is prescribed to patients to alleviate symptoms of heart failure by strengthening contractions, helping the heart pump blood more effectively. Digoxin can also be used to treat arrhythmias. It cannot be used to cure heart failure or arrhythmias but can help to manage the symptoms along with other medication, exercise and diet.
Digoxin levels are monitored due to the drug’s narrow safety range. If the level is too high, toxicity may occur, if too low, symptoms may recur.
• Monitor the concentration of the drug in the patient's blood • Determine if a patient's symptoms are due to insufficient levels of Digoxin or due to digoxin toxicity • Increase the strength and efficiency of heart contractions, helping control the rate and rhythm of the heart • Slows electrical conduction between the atria and the ventricles, which is useful in treating abnormally rapid atrial rhythms that can cause heart attacks Luteinizing Hormone (LH)
Luteinizing Hormone (LH) is associated with the reproductive cycle and the release of an egg from the ovary in women and testosterone production in men. LH production is a complex system controlled by the hypothalamus in the brain, hormones produced in the testes and ovaries, and the pituitary gland.
This test measures the amount of luteinizing hormone in the blood or urine. It is used alongside other tests such as FSH, estradiol, progesterone, and testosterone to investigate reproductive irregularities.
A luteinizing hormone level may be used [4]:
In both men and women:
• In the workup of infertility • To aid in the diagnosis of pituitary disorders that can affect LH production • To help diagnose conditions associated with dysfunction of the ovaries or testicles In women:
• In the investigation of menstrual irregularities • To detect a surge in LH levels during the menstrual cycle, helping determine when a woman is likely to be the most fertile In children:
• To diagnose delayed and precocious (early) puberty. Irregular timing of puberty may be an indication of a more serious problem involving the hypothalamus, the pituitary gland, the ovaries or testicles, or other systems Insulin
Insulin is a hormone produced and stored in the beta cells of the pancreas. It is secreted as a response to an elevated glucose level following a meal and is vital in the transportation and storage of glucose, the body’s primary source of energy. Insulin regulates blood glucose by helping transport it from blood to cells.
This test measures the amount of insulin in the blood. After a meal, carbohydrates are broken down into glucose, this is then absorbed into the blood causing the blood glucose level to rise, this then falls as it moves into cells. If an individual cannot produce enough insulin, or if they are insulin resistant (cells are resistant to insulin’s effects), glucose does not reach the body’s cells and they starve. The blood glucose level will rise to an unhealthy level, which can cause various complications, including Diabetes.
An insulin level may be used to [5]:
• Diagnose an insulinoma, verify that removal of the tumor has been successful, and/or to monitor for recurrence • Diagnose the cause of hypoglycemia in an individual with signs and symptoms • Identify insulin resistance • Monitor the amount of insulin produced by the beta cells in the pancreas (endogenous); in this case, a C-peptide test may also be done. Insulin and C-peptide are produced by the body at the same rate as part of the conversion of proinsulin to insulin in the pancreas • Determine when a type 2 diabetic might need to start taking insulin to supplement oral medications • Determine and monitor the success of an islet cell transplant intended to restore the ability to make insulin, by measuring the insulin-producing capacity of the transplant What test results mean [5]:
DisorderFasting Insulin LevelFasting Glucose LevelInsulin resistance High Normal or somewhat elevated Not enough insulin produced in beta cells (diabetes, pancreatitis) Low High Hypoglycemia due to excess insulin (insulinomas, cushing syndrome) Normal or High Low
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References
[1] “Androstenedione”, Labtestsonline.org, 2017. [Online]. Available: https://labtestsonline.org/tests/androstenedione. [Accessed: 07- Aug- 2018].
[2] “Digoxin”, Labtestsonline.org, 2017. [Online]. Available: https://labtestsonline.org/tests/digoxin. [Accessed: 08- Aug- 2018].
[3] O. Ogbru and J. Marks, “digoxin, Lanoxin: Drug Facts, Side Effects and Dosing”, MedicineNet. [Online]. Available: https://www.medicinenet.com/digoxin/article.htm#which_drugs_or_supplements_interact_with_digoxin?. [Accessed: 08- Aug- 2018].
[4] “Luteinizing Hormone (LH)”, Labtestsonline.org, 2017. [Online]. Available: https://labtestsonline.org/tests/luteinizing-hormone-lh. [Accessed: 08- Aug- 2018].
[5] “Insulin”, Labtestsonline.org, 2017. [Online]. Available: https://labtestsonline.org/tests/insulin. [Accessed: 08- Aug- 2018].
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Product Spotlight: Acusera Immunoassay Speciality 2 Control
The Randox Acusera Immunoassay Speciality II quality control is designed to complement our Immunoassay Premium and Premium Plus controls. Assayed, instrument specific target values and ranges are provided for 4 complex immunoassay parameters.
Features & Benefits
- Lyophilised for enhanced stability
- 100% human serum
- Assayed target values provided for 4 parameters
- Stable to expiry date at 2°C – 8°C
- Reconstituted stability of up to 5 days at 2°C – 8°C and 4 weeks at -20°C
Procalcitonin
Procalcitonin (PCT), a protein that consists of 116 amino acids, is the peptide precursor of calcitonin, a hormone that is synthesized by the parafollicular C cells of the thyroid and involved in calcium homeostasis.
Procalcitonin is also produced by the neuroendocrine cells of the lung and intestine and is released as an acute-phase reactant in response to inflammatory stimuli, especially those of bacterial origin. This raised procalcitonin level during inflammation is associated with bacterial endotoxin and inflammatory cytokines.
Procalcitonin (PCT) versus C-reactive protein (CRP)
CRP is the most common laboratory marker used in the clinical setting to evaluate systemic inflammatory response to an infectious agent.
Procalcitonin is a more useful diagnostic inflammation parameter than CRP in patients with pediatric neutropenic fever, both in estimating the severity of infection and the duration and origin of the fever. Procalcitonin is also a more reliable parameter in the diagnosis of bacterial sepsis, allowing better differentiation among sepsis-related fatalities.[2]
Calcitonin
A calcitonin assay is helpful in identifying patients with nodular thyroid disease. It is often performed in the hope of identifying early MTC. Successful treatment of MTC depends on early detection; late detection confers a poor prognosis. In addition, calcitonin levels are reported to be increased in other malignancies, such as carcinoid tumors, lung carcinoma, melanoma, pancreatic and breast carcinoma, and pheochromocytoma.
Calcitonin is produced and released by parafollicular cells of the thyroid. Calcitonin is derived from larger precursors. Precalcitonin is cleaved to procalcitonin, which is further cleaved to immature calcitonin and then to mature calcitonin, a monomer of a 3.5-kd peptide composed of 32 amino acids, which is the only biologically active form.
Calcitonin’s precise physiologic role in humans remains to fully understood. It is known to act on the bones, kidneys, and gastrointestinal tract, binding directly to osteoclasts, thereby directly inhibiting osteoclastic bone resorption. Although this inhibition may be important in short-term control of calcium loads, it is short-lived and likely plays an insignificant role in overall calcium homeostasis. Calcitonin also inhibits the action of parathyroid hormone and vitamin D. [1]
Gastrin
Gastrin testing is employed in the diagnosis of gastrinoma, either with or without Zollinger-Ellison syndrome, and in the investigation of pernicious anemia and achlorhydria.
In patients who have undergone antrectomy with vagotomy, gastrin levels are reduced. In contrast, gastrin levels are increased in Zollinger-Ellison syndrome.[3]
Renin
Renin, also known as Angiotensinogenase, is an enzyme involved in the renin–angiotensin aldosterone system (RAAS), which regulates the body’s water balance and blood pressure level. The system regulates the extracellular volume in the blood plasma, lymph and interstitial fluid, as well as controlling constriction of the arteries and blood vessels.[5] It is secreted by the kidney from specialized cells called granular cells and has a fundamental role in hypertension development. Over activation of this system contributes to hypertension and associated end-organ damage.[4]
The secretion of renin is stimulated by the following three factors:
-
- When a fall in arterial blood pressure is detected by pressure sensitive receptors (baroreceptors) in the arterial vessels.
- When a decrease in sodium chloride (salt) is detected in the kidney by the macula densa in the juxtaglomerular apparatus.
- When sympathetic nervous system activity is detected through beta1 adrenergic receptors.[4]
-
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References
[1]A. Sofronescu and E. Staros, “Calcitonin”, Emedicine.medscape.com, 2015. [Online]. Available: https://emedicine.medscape.com/article/2087580-overview#a4. [Accessed: 16- Jul- 2018].
[2]J. Lin, S. Yap and E. Staros, “Procalcitonin”, Emedicine.medscape.com, 2015. [Online]. Available: https://emedicine.medscape.com/article/2096589-overview#a4. [Accessed: 16- Jul- 2018].
[3]B. Devkota and E. Staros, “Gastrin”, Emedicine.medscape.com, 2014. [Online]. Available: https://emedicine.medscape.com/article/2089092-overview#a4. [Accessed: 16- Jul- 2018].
[4]T. Meštrović, “Renin Clinical Applications”, News-Medical.net, 2015. [Online]. Available: https://www.news-medical.net/health/Renin-Clinical-Applications.aspx. [Accessed: 16- Jul- 2018].
[5]D. Mandal, “Renin (Angiotensinogenase)”, News-Medical.net, 2014. [Online]. Available: https://www.news-medical.net/health/Renin-Angiotensinogenase.aspx. [Accessed: 16- Jul- 2018].
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Product Spotlight: Molecular QC and EQA for Infectious Disease Testing
Earlier in the year, Randox entered into a strategic partnership, bringing on-board Qnostics Molecular Controls and QCMD Molecular EQA which comprises hundreds of controls and EQA programmes for molecular infectious disease testing.
The Global Molecular Diagnostics market is estimated to be worth 6.54 billion USD. This market is classified into infectious diseases, oncology, genetic tests and blood screening. Infectious diseases account for the largest share of the global market.
According to the World Health Organisation (WHO), Infectious Diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi. These diseases can be spread – directly or indirectly – from one person to another.
Designed to meet the demands of today’s molecular diagnostics laboratory and laboratories carrying out Nucleic Acid Testing (NAT), the Qnostics range comprises hundreds of characterised viral, bacterial and fungal targets covering a wide range of Transplant Associated Diseased, Respiratory Diseases, Blood Borne Viruses, Sexually Transmitted Infections, Gastro-Intestinal Diseases and Central Nervous System Diseases.
Qnostics products can be used in the daily monitoring of assay performance, linearity assessment, assay evaluation, validation/verification of new assays and staff training.
There are five main product areas for Qnostics:
Product Groups (click to expand)
Q Controls
Independently manufactured, this range of positive run, whole pathogen, third party controls are designed to monitor the daily performance of a wide of range molecular assays used in the detection of infectious diseases. These controls help in supporting a laboratory’s accreditation requirements, in line with ISO 15189:2012.Analytical Q Panels
Designed to cover the dynamic range of an assay, Analytical Q Panels allow assessment of an assays linearity, LOD and LOQ. Each panel contains a minimum of five samples, including a negative that spans the dynamic range of the assay in a linear progression.Molecular Q Panels
Consisting of three levels (high, medium and low), Molecular Q Panels are intended to evaluate an assays analytical measuring range. Molecular Q Panels can also be used to support training of laboratory staff and in the development of molecular diagnostic assays.Evaluation Panels
Evaluation Panels cover a range of genotypes and may be used to evaluate assay characteristics, confirm performance claims and ultimately ensure the assay is fit for purpose. Evaluation Panels may also be used in the validation of molecular assays and development of new molecular diagnostic assays.QCMD Past Panels
Available for use in assay evaluation and staff training, EQA samples are available from past QCMD challenges.Custom ManufactureQnostics are specialists in the custom manufacture of quality control materials for use in the detection of infectious diseases using molecular based methods. Qnostics will work with you to develop a bespoke solution designed specifically to meet the individual and unique requirements of your lab.
- Choose from hundreds of molecular characterised targets
- Targets can be custom made into numerous different formats
- The whole pathogen format accurately mimics clinical samples
- All materials can be provided in a “ready-to-use” or liquid frozen format
Qnostics custom made Molecular Infectious Disease Controls are designed to fit all stages of your assays product life cycle from product development to launch.
QCMD is a world leading External Quality Assessment (EQA) / Proficiency Testing (PT) scheme, dedicated to improving the quality of molecular diagnostic assays used in the detection of infectious diseases.
With an extensive database of over 2000 participants in over 100 countries, QCMD is one of the largest providers of molecular EQA in the field of infectious disease testing.
EQA participants receive an individual report outlining their performance relative to their method and technology groups. A supplementary report may be commissioned – this includes any additional relevant information regarding the annual EQA distribution, as well as scientific expert commentary and feedback on the overall results within that distribution.
Features & Benefits (click to expand)
Frequency
A variety of programme options are available. Choose the number of challenges that best suit your laboratory’s requirements.
Online EQA Management System
ITEMS provides an online tool to easily manage all EQA activities from programme registration to submission of results and provision of EQA reports. Different levels of user access are available so data can be accessed by whoever needs it.
High level of participation
Over 2000 participants in more than 100 countries ensuring peer group numbers are maximised.
Comprehensive reports
Receive individual reports for each challenge and a final supplementary report at the end of the cycle visual assessment of performance.
International accreditation
Programmes are accredited to ISO 17043.
Qnostics
QCMD
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Complete QC Solutions for Results you can Trust
Randox is one of the largest manufacturers of true third party quality control solutions. With over 35 years’ experience delivering reliable, high quality products designed to effectively challenge instrument performance you can be confident in the accuracy of patient test results, whilst reducing time and costs. With more than 390 analytes available across the Acusera range and a wide range of formats providing flexibility & choice, we have a solution to suit you.
Our diverse range of multi-analyte, third party controls offer industry leading opportunities for consolidation, ultimately delivering cost savings, reduced preparation time and increased efficiency all without compromising on quality. Manufactured using the highest quality raw materials, lot to lot consistency and unrivalled commutability is guaranteed, ensuring performance mirrors that of the patient sample and costly shifts in QC results are reduced.
Benefits
Consolidation
Specialising in consolidation, the Acusera range of multi-analyte controls is designed to reduce the number of individual controls required to cover your test menu, ultimately reducing costs, preparation time and storage space.Commutability
All Acusera controls are designed to react to the test system in the same manner as the patient sample, helping to meet ISO 15189:2012 requirements whilst reducing inconvenient and costly shifts in QC results when reagent batch is changed.Clinically Relevant Levels
The presence of analytes at key decision levels not only helps to ensure accurate instrument performance but maximises laboratory efficiency by eliminating the need for additional low/high level controls at extra expense.Reduced Waste
The unrivalled working stability of the Acusera control range helps to keep waste and costs to a minimum.Flexibility
With an extensive range of assayed/unassayed, liquid/lyophilised and single/multi-analyte controls, the Acusera portfolio has a solution to suit all laboratory preferences.True Third Party Controls
Manufactured independently, the Acusera range delivers unbiased performance assessment with any instrument or method, helping to meet ISO 15189:2012 requirements whilst simultaneously eliminating the need for multiple instrument dedicated controls.
Choose below to find a control that suits you.
Complementing our Internal Quality Control range is Acusera 24•7, a powerful data management tool designed to help even the most demanding laboratories manage their daily QC activities. Delivering unique access to real-time peer group statistics, a variety of fully interactive charts and automatic calculation of performance metrics such as Measurement Uncertainty, Acusera 24•7 will speed up data review and troubleshooting.
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RX series (Concept 3)
The RX series range of clinical chemistry analysers includes both semi-automated and fully automated testing for a range of clinical settings. With a world leading test menu comprising of routine chemistries, specific proteins, lipids, therapeutic drugs, drugs of abuse, antioxidants and diabetes testing, the RX series offers laboratories the complete clinical chemistry package and results you can trust. The RX series was built with three core values in mind – Reliability, Accuracy and Precision.
Consolidation of Routine & Specialised Testing on One Single Platform
With an extensive product portfolio covering over 100 disease markers within routine and nice testing, the RX series removes the need for a separate nephelometry system for specific proteins and allows laboratories to bring all testing in-house; thus ensuring minimal downtime and providing real cost savings through consolidation.
Low Reagents & Sample Volumes
Built with excellence in mind, the RX series range of analsyers require a low sample volume to deliver consistent high quality results which is beneficial when working with paediatric patients and animals. Combined with our high quality reagents, the RX series reduce the possibility of misdiagnoses, offering accurate, reliable and precise results each time, every time.
Unrivalled Customer Support
Our team of trained engineers are on hand to work with you in preserving the continuity of your operations while maximising the potential of your RX series instrument. We know time is critical in any laboratory and our global network means we are uniquely positioned to meet your needs with local service and support whenever you need it.
Fully Automated
Test Menu
Semi-Automated
Test Menu
Niche
Test Menu
QCMD – Molecular External Quality Control
QCMD is a world leading External Quality Assessment (EQA) / Proficiency Testing (PT) scheme, dedicated to improving the quality of molecular diagnostic assays used in the detection of infectious diseases.
With an extensive database of over 15,000 participants in over 100 countries, QCMD is one of the largest providers of molecular EQA in the field of molecular diagnostics.
Blood Borne Viruses
Central Nervous System Diseases
Drug Resistance
Exotic / Emerging Diseases
Gastrointestinal Diseases
Immunocompromised Associated Diseases
Multiple Pathogen / Syndromic Infections
Respiratory Diseases
Serology
Sexually Transmitted Infections
Transplant Associated diseases
Typing
New Pilot Studies
After the close of the results return phase, EQA participants will receive an individual report outlining their performance relative to their method and technology groups. A supplementary report may be commissioned – this includes any additional relevant information regarding the annual EQA distribution, as well as scientific expert commentary and feedback on the overall results within that distribution.
*Randox are authorised by QCMD to provide the QCMD EQA schemes under a strategic global partnership. The EQA design, composition, data analysis & reporting remain the responsibility of QCMD. Please refer to specific geographical regions for further details on availability.
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Measurement Uncertainty Vs Total Error
In a recent article, Error Methods Are More Practical, But Uncertainty Methods May Still Be Preferred, James Westgard comments on the latest developments in the debate on the use of analytical total error (TE) and measurement uncertainty (MU), a debate which has been regularly revisited for the last twenty years. This blog aims to briefly explore the benefits of MU and TE and attempt to draw a conclusion on which is most beneficial in the clinical laboratory.
Many things can undermine a measurement. Measurements are never made under perfect conditions and in a laboratory, errors and uncertainties can come from (Good Practice Guide No. 11, 2012):
- The measuring instrument – instruments can suffer from errors including bias, changes due to ageing, wear, poor readability, and noise.
- The item being measured – the sample may be unstable.
- The measurement process – the analyte may be difficult to measure
- ‘Imported’ uncertainties – calibration of the instrument.
- User error – skill and judgement of the operator can affect the accuracy of a measurement.
- Sampling issues – the measurements you make must be properly representative of the process you are trying to assess. I.e. not using fully commutable controls will mean your quality control process is not reflective of a true patient sample.
Random and systematic errors
The effects that give rise to uncertainty in a measurement can be either random or systematic, below are some examples of these in a laboratory.
- Random – bubbles in reagent, temperature fluctuation, poor operator technique.
- Systematic – sample handling, reagent change, instrument calibration (bias), inappropriate method.
Total Error (TE) or Total Analytical Error (TAE) represents the overall error in a test result that is attributed to imprecision (%CV) and inaccuracy (%Bias), it is the combination of both random and systematic errors. The concept of error assumes that the difference between the measured result and the ‘true value’, or reference quantity value, can be calculated (Oosterhuis et al., 2017).
TE is calculated using the below formula:
TE = %BIAS + (1.96 * %CV)
Measurement Uncertainty is the margin of uncertainty, or doubt, that exists about the result of any measurement.
There is always margin of doubt associated with any measurement as well as the confidence in that doubt, which states how sure we are that the ‘true value’ is within that margin. Both the significance, or interval, and the confidence level are needed to quantify an uncertainty.
For example, a piece of string may measure 20 cm plus or minus 1 cm with a 95% confidence level, so we are 95% sure that the piece of string is between 19 cm and 21 cm in length (Good Practice Guide No. 11, 2012).
Standards such as ISO 15189 require that laboratories must determine uncertainty for each test. Measurement Uncertainty is specifically mentioned in section 5.5.8.3:
“The laboratory shall determine measurement uncertainty for each measurement procedure in the examination phases used to report measured quantity values on patients’ samples. The laboratory shall define the performance requirements for the measurement uncertainty of each measurement procedure and regularly review estimates of measurement uncertainty.”
Uncertainty is calculated using the below formula:
u = √A2+B2
U = 2 x u
Where:
A = SD of the Intra-assay precision
B = SD of the Inter-assay precision
u = Standard Uncertainty
U = Uncertainty of Measurement
Error methods, compared with uncertainty methods, offer simpler, more intuitive and practical procedures for calculating measurement uncertainty and conducting quality assurance in laboratory medicine (Oosterhuis et al., 2018).
It is important not to confuse the terms ‘error’ and ‘uncertainty’.
- Error is the difference between the measured value and the ‘true value’.
- Uncertainty is a quantification of the doubt about the measurement result.
Whenever possible we try to correct for any known errors: for example, by applying corrections from calibration certificates. But any error whose value we do not know is a source of uncertainty (Good Practice Guide No. 11, 2012).
While Total Error methods are firmly rooted in laboratory medicine, a transition to the Measurement Uncertainty methods has taken place in other fields of metrology. TE methods are commonly intertwined with quality assurance, analytical performance specifications and Six Sigma methods. However, Total Error and Measurement Uncertainty are different but very closely related and can be complementary when evaluating measurement data.
Whether you prefer Measurement Uncertainty, Total Error, or believe that they should be used together, Randox can help. Our interlaboratory QC data management software, Acusera 24•7, automatically calculates both Total Error and Measurement Uncertainty. This makes it easier for you to meet the requirements of ISO:15189 and other regulatory bodies.
This is an example of the type of report generated by the 247 software. MU is displayed for each test and each lot of control in use therefore eliminating the need for manual calculation and multiple spreadsheets.
Fig. A
Fig. B
Fig. A and Fig. B above are examples of report generated by the 24•7 software. Fig.A shows how MU is displayed for each test and each lot of control in use therefore eliminating the need for manual calculation and multiple spreadsheets. Fig. B shows TE displayed for each test.
Acusera Third Party Controls
The Importance of ISO 15189
Good Practice Guide No. 11. (2012). Retrieved from http://publications.npl.co.uk/npl_web/pdf/mgpg11.pdf
Hill, E. (2017). Improving Laboratory Performance Through Quality Control.
Oosterhuis, W., Bayat, H., Armbruster, D., Coskun, A., Freeman, K., & Kallner, A. et al. (2017). The use of error and uncertainty methods in the medical laboratory. Clinical Chemistry and Laboratory Medicine (CCLM), 56(2). http://dx.doi.org/10.1515/cclm-2017-0341
Westgard, J. (2018). Error Methods Are More Practical, But Uncertainty Methods May Still Be Preferred. Clinical Chemistry, 64(4), 636-638. http://dx.doi.org/10.1373/clinchem.2017.284406
Product Spotlight: Liquid Assayed Chemistry Premium Plus
Routine clinical chemistry is the basis of a laboratory’s daily testing, it is, therefore, important to choose a chemistry control which offers the greatest consolidation, accuracy, and stability.
The Acusera Liquid Assayed Chemistry Premium Plus control is one of the most comprehensive chemistry controls on the market, with instrument specific values provided for 99 analytes. A unique combination of proteins, lipids, cardiac markers, therapeutic drugs, immunoassay, and routine chemistry parameters enables effective consolidation, as well as time and cost savings. As a true third party control, it is manufactured independently from any analyser, with values assigned using our unique value assignment process, target values are available for several common analyser platforms. Containing an impressive array of lipids and Immunoassay parameters, this Acusera Chemistry control offers unrivaled consolidation.
Key Features & Benefits
- Liquid for ease of use
- Human based serum
- Assayed instrument specific target values and ranges
- High levels of CRP and other proteins eliminate the need for multiple controls
- Stable to expiry when stored at -20°C to -70°C
- Open vial stability of up to 7 days at 2°C – 8°C
Analytes (click to expand)
Albumin (Electrophoresis)
Alpha-1-Globulin (Electrophoresis)
Alpha-2-Globulin (Electrophoresis)
Beta-Globulin (Electrophoresis)
Gamma-Globulin (Electrophoresis)
Alpha-HBDH
α-1- Acid Glycoprotein
α-1-Antitrypsin
Β-2-Microglobulin
Acid Phosphatase (Total)
AFP
Albumin
Alkaline Phosphatase
Amikacin
ALT
Amylase
Amylase (Pancreatic)
Apo A-1
Apo B
AST
Bicarbonate
Bile Acids
Bilirubin Direct
Bilirubin Total
C-Reactive Protein
Caffeine
Calcium
Carbamazepine
CEA
Ceruloplasmin
Chloride
Cholesterol
CholinesteraseCK Total
Complement C3
Complement C4
Copper
Cortisol
Creatinine
D-3-Hydroxybutyrate
DHEA Sulphate
Digoxin
Ethanol
Ferritin
Folate
FSH
Free T3
Free T4
Gamma GT
Gentamicin
GLDH
Glucose
Haptoglobin
hCG
HDL Cholesterol
IgA
IgE
IgG
IgM
Iron
Lactate
LAP
LDH
LDL Cholesterol
Leutinising Hormone
LipaseLP(a)
Lithium
Magnesium
Myoglobin
Osmolality
Paracetamol
Phenobarbital
Phenytoin
Phosphate Inorganic
Potassium
Prealbumin
Progesterone
Prolactin
Protein Total
PSA Total
Salicylate
Sodium
Testosterone
Theophylline
Total T3
Total T4
TSH
TIBC
Transferrin
Triglycerides
Troponin T
T Uptake
Urea
Uric Acid
Valproic Acid
Vancomycin
Vitamin B12
Zinc
C-Reactive Protein (CRP)
CRP is a protein made by the liver and released into the blood within a few hours after tissue injury, the start of an infection, or other cause of inflammation. It is tested to detect the presence of inflammation and can be used to monitor the response to treatment for inflammatory disorders. CRP is included in the Liquid Assayed Chemistry Premium Plus control, ensuring accurate instrument performance at key decision levels and further reduces the number of individual controls required. CRP is available at elevated levels in the level three control.
Troponin T (TnT)
A troponin test measures the levels of troponin proteins in blood and is used when a patient is suspected to have suffered a heart attack. These proteins are released when the heart muscle has been damaged, such as with a heart attack. More damage to the heart would result in a higher level of Troponin T. As a highly consolidated contorol, the Liquid Assayed Chemistry Premium Plus includes Troponin T, meaning a separate control is not required.