Benefits of the Randox H-FABP (Cardiac) Assay
The Randox latex enhanced immunoturbidimetric (L.E.I) method offers a more convenient, high performing and time efficient (results in 14 minutes, depending on analyser) method compared to traditional ELISA testing.
A correlation coefficient of r=0.97 was displayed when the Randox methodology was compared against commercially available methods.
Wide measuring range
The Randox H-FABP assay can comfortably detect levels outside of the healthy range, measuring between 0.747 – 120ng/ml.
Liquid ready-to-use assay
The Randox H-FABP assay is available in a liquid ready-to-use format for convenience and ease-of-use.
Dedicated calibrator and controls available
Dedicated H-FABP calibrator and controls available offering a complete testing package.
Applications available detailing instrument-specific settings for the convenient use of the Randox H-FABP assay on a variety of clinical chemistry analysers.
Fatty acid-binding proteins (FABPs) are small cytoplasmic proteins that are abundantly expressed in tissues with an active fatty acid metabolism, including the heart and liver. Heart-type fatty acid-binding protein (H-FABP) is an unbound, low molecular weight protein (15kDa), located in the cytoplasm of cardiac myocytes 1 2.
The primary function of H-FABP is to transport intracellular long-chain fatty acids. When compared to traditional cardiac proteins, H-FABP is smaller than myoglobin (18kDa), troponin I (TnI) (22kDa), troponin T (TnT) (37kDa) and creatine kinase-muscle/brain (CK-MB) (86kDa) 3. H-FABP freely circulates in the cytoplasm, this coupled with its low molecular weight makes, H-FABP a more reliable and sensitive indicator of at-risk patients as indicated in Fig 1.
Fig 1. The early release of H-FABP following myocardial infarction (MI) 3
H-FABP has been studied as a cardiac biomarker since the early 1990s however, early progress in clinical studies was hampered due to the lack of monoclonal antibodies and high quality (quantitative) assays. Gradual improvements in H-FABP antibodies and assays over recent years means that the true clinical value of the biomarker is now evident. Several key publications advocate the early diagnosis of ACS utilising the H-FABP test:
1. JAMA (2011): Serial changes in highly sensitive troponin I assay and early diagnosis of myocardial infarction 4
Objective: A study prospectively evaluated 1,813 patients with suspected ACS were consecutively enrolled at the chest pain units of the University Heart Centre Hamburg, Germany on admission and after 3 and 6 hours, A variety of biomarkers were measured at each time point.
Conclusion: H-FABP offer superior diagnostic performance or acute myocardial infarction (AMI) compared to a range of novel ACS biomarkers (based on the ROC analysis produced in this study).
2. Scandinavian Journal of Clinical and Laboratory Investigation (2012): Clinical and analytical evaluation of an immunoturbidimetric heart-type fatty acid-binding protein assay 5
Objective: A study prospectively evaluated patient samples and pools of samples to assess functional sensitivity, linearity, precision, limit of detection, recovery of recombinant H-FABP with troponin in samples routinely received from chest patient samples.
Conclusion: H-FABP an be run in a bury routine laboratory and on non-proprietary analytic platforms, offering excellent performance and precision.
Chest pain is a common symptom for patients reporting to an emergency department (ED), representing ≈10% of all ED consultations. It is vital that patients who present with chest pain of suspected cardiac origin are screened for ACS. Only 10% to 20% of these patients will be diagnosed as experiencing an acute myocardial infarction (AMI) 6.
Recently, high sensitivity troponin has made its way onto the market. H-FABP is not a replacement test for hs-TnT/ hs-TnI, however, measurement of H-FABP in combination with hs-TnT/hs-TnI is optimal for improving the early diagnosis of ACS and can offer clinical utility in the ED. Recent publications advocate testing H-FABP in combination with high sensitivity troponin (hs-TnT or hs-TnI) for optimal performance:
1. BMC Emergency Medicine (2016): Heart-type fatty acid-binding protein and cardiac troponin: development of an optimal rule-out strategy for acute myocardial infarction 7
Objective: A study prospectively evaluated hd-TnI, hsTnT and H-FABP in 1,016 patients presenting at a New Zealand ED with symptoms triggering investigation for possible ACS.
Conclusion: H-FABP in combination with hs-TnI without ischaemic ECG changes improved the rule-out of AMI upon presentation at an ED, compared to hs-TnI and ECG, while maintaining >99% sensitivity for AMI. The implementation of this strategy would enable up to 40% of patients to be classed as low risk and suitable for early discharge, reducing the number of in-hospital stays.
2. Journal of Clinical and Experimental Cardiology (2018): Diagnostic performance of a combination biomarker algorithm for rule-out of acute myocardial infarction at time of presentation to the emergency department, using heart-type fatty acid-binding protein and high-sensitivity troponin T tests 8
Objective: A study prospectively examine 548 patients with suspected cardiac chest pain presenting at a hospital ED in Northern Ireland for the development of a rule-out algorithm based H-FABP and hs-TnT. Blood samples were collected at presentation and after 1, 2, 3, 6, 12 and 24 hours and 20 parameters were measured.
Conclusion: The implementation of a combined H-FABP hs-TnT algorithm at an ED could aid in the identification of non-AMI patients on arrival, with the potential to reduce hospital admission by 36.8%. Moreover, this combined algorithm could potentially have a significant impact on patient health, ensuring the appropriate and effective implementation of a treatment plan for patients identified as high risk.
Not only is H-FABP useful in the diagnosis of cardiac conditions such as ACS or AMI, it also offers clinical utility in the prognosis of cardiac conditions.
1. The American Journal of Cardiology (2009): Prognostic value of a multimarker approach for patients presenting to hospital with acute chest pain 9
Objective: A study prospectively examined 664 patients exhibiting acute ischaemic-type chest pain. The study evaluated novel biomarkers of myocardial injury, neurohormonal activity, haemostasis, and vascular inflammation. Those of greatest significance were tested in the risk stratification during the 1 year follow up.
Conclusion: The measurement of H-FABP upon hospital admission provides useful prognostic value compared to the measurement of baseline and 12-hour TnT.
In addition to significant diagnostic values in ACS, H-FABP has been consistently and robustly shown to offer significant value in the long-term prognosis of ACS patients, even when compared to hs-troponin assays10. Several key publications advocate the long-term prognosis of patients utilising the H-FBP test:
1. Journal of the American College of Cardiology (2010): Heart-type fatty acid-binding protein predicts long-term mortality and re-infarction in consecutive patients with suspected acute coronary syndrome who are troponin negative 11
Objective: A study prospectively evaluated 995 patients presenting with suspected ACS. Utilising the ultra-TnI and the Randox Randox assays, samples were collected 12 to 24 hours following the onset of symptoms.
Conclusion: The prognostic value of elevated H-FABP levels is additive to troponin in low and intermediate risk patients with suspected ACS. The long-term prognostic value of H-FABP in troponin-negative patients is independent of age and serum creatinine.
2. British Medical Journal (2011): In acute coronary syndromes, heart-type fatty acid-binding protein is a more accurate predictor of long term prognosis then troponin 12
Objective: A study prospectively examined 1,448 ACS patients who had serum H-FABP levels measured upon hospital admission. The study provides a six-year mortality overview following on from the one-year mortality data published in 2007.
Conclusion: Whilst the patterns between both studies are very similar, except for TnI- / H-FABP+ group of patients. The TnI- / H-FABP+ cohort exhibit the highest mortality rates after six years. Not only is H-FABP an independent prognostic marker but it also identifies high-risk patients who are TnI negative.
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Reagents Resource Hub
 Release of fatty acid-binding protein from isolated rat heart subjected to ischemia and reperfusion or to the calcium paradox. Glatz, J F, et al. 52, Maastricht : The Clinical Biochemist, 1988, Vol. 148.
 Clinical study of H-FABP for risk stratification and prognosis in patients with early cTnT-negative ACS. Liu, Yawei, et al. Beijing : Internal Journal of Clinical and Experimental Medicine, 2017. 1940-5901.
 Al-Dabbagh, Ihsan Hassan. Heart type fatty acid binding protein H-FABP. College of Medicine-Mosul. [Online] [Cited: November 06, 2018.] http://medicinemosul.uomosul.edu.iq/files/news/news_4087987.pdf.
 Supplementary Online Content: Serial Changes in Highly Sensitive Troponin I Assay and Early Diagnosis of Myocardial Infarction. Keller, T, Zeller, Tanja and Ojeda, Francisco. Hamburg : JAMA, 2011.
 Clinical and analytical evaluation of an immunoturbidimetric heart-type fatty acid-binding protein assay. Carless, Daniel R, et al. 1, s.l. : Scandinavian Journal of Clinical and Laboratory Investigation, 2013, Vol. 73.
 Misdiagnosis of Myocardial Infarction Related to Limitations of the Current Regulatory Approach to Define Clinical Decision Values for Cardiac Troponin. Wildi, Karin, et al. Trimbach : Circulation, 2015.
 Heart Fatty Acid Binding Protein and cardiac troponin: development of an optimal rule-out strategy for acute myocardial infarction. Young, Joanna M, et al. Christchurch : BMC Emergency Medicine, 2016.
 Diagnostic Performance of a Combination Biomarker Algorithm for Rule-Out of Acute Myocardial Infarction at Time of Presentation to the Emergency Department, Using Heart-Type Fatty Acid-Binding Protein and High-Sensitivity Troponin T tests. Navarro, César O, et al. Belfast : Journal of Clinical and Experimental Cardiology, 2018.
 Heart-Type Fatty Acid-Binding Protein Predicts Long-Term Mortality and Re-Infarction in Consecutive Patients With Suspected Acute Coronary Syndrome Who Are Troponin-Negative. Viswanathan, Karthik, et al. 23, Leeds : Journal of the American College of Cardiology, 2010, Vol. 55. 0735-1097.
 Heart-type fatty acid-binding protein (H-FABP) and highly sensitive troponin T (hsTnT) as markers of myocardial injury and cardiovascular events in elective percutaneous coronary intervention (PCI). Connolly, M, et al. 1, Belfast : QJM: An International Journal of Medicine, 2017, Vol. 111.