Cleartest light H-FABP / Troponin I

The CLEARTEST® light H-FABP/ Troponin I rapid test is a rapid chromatographic immunoassay for the qualitative detection of human H-FABP and cardiac troponin I (cTnI) in whole blood, serum or plasma as an aid in the diagnosis of myocardial infarction (MI). The detection limit is 8 ng/ml H-FABP and 0.5 ng/ml Troponin I. The test is for professional in vitro diagnostic use only.

FABP is a newly introduced plasma marker for acute myocardial infarction (AMI). The plasma kinetics of FABP (15 kD) closely resemble that of myoglobin in that elevated plasma concentrations are found within 2 hours of an AMI and generally return to normal within 18 to 24 hours. However, the concentration of FABP in skeletal muscle is 20 times lower than in cardiac tissue (whereas the myoglobin content in cardiac and skeletal tissue is the same), making FABP more heart-specific than myoglobin. For this reason, FABP is a useful biochemical marker for the early assessment or exclusion of AMI. FABP also appears to be a useful plasma marker for estimating the size of the myocardial infarction. FABP is suitable for use as a standard in immunoassays for the early detection of acute myocardial infarction, as an immunogen for the preparation of antisera, as a bulk FABP standard, and for biochemical and immunochemical FABP assays and tracers for iodination.

Troponin I (cTnI) is a protein found in the heart muscle with a molecular weight of 22.5 kDa. Troponin I is part of a complex of three subunits, consisting of troponin T and troponin C. Together with tropomyosin, this structural complex forms the main component regulating the calcium-sensitive ATPase activity of actomyosin in striated skeletal and cardiac muscles. As a result of cardiac injury, troponin I is released into the blood 4-6 hours after the onset of pain. The release pattern of cTnI is similar to CK-MB, but while CK-MB levels return to normal after 72 hours, troponin I remains elevated for 6-10 days, providing a longer window of detection for cardiac injury. The high specificity of cTnI measurements for identifying myocardial damage has been demonstrated in conditions such as the perioperative period, after marathon runs and blunt thoracic trauma. The cTnI release has also been documented in cardiac conditions other than acute myocardial infarction (AMI), such as unstable angina, decompensated heart failure and ischaemic damage due to coronary artery bypass grafting.

Performance characteristics

- Sensitivity, specificity and accuracy

H-FABP

Sensitivity: 89.9% (95% CI*: 80.2%~95.8%)

Specificity: 91.0 % (95 % CI*: 86.4 %~94.5 %)

Accuracy: 90.7 % (95 % CI*: 86.7 %~93.9 %)

Troponin I

Sensitivity: 99.4 % (95 % CI*: 96.8 %~99.9 %)

Specificity: 99.0 % (95 % CI*: 97.6 %~99.7 %)

Accuracy: 99.1 % (95 % CI*: