Evaluation of the Haemolysis Effect on the Measurement of Troponin T using the Roche Modular System

Jessie Raju, Biochemistry

Raju J and Kennedy D

Good Hope Hospital, Heart of England Foundation Trust, Sutton Coldfield

Cardiac troponin T (cTnT) is a sensitive and specific biochemical marker of myocardial infarction and has a high prognostic value in determining future adverse events in patients with acute coronary syndromes.

The aim of the study was to determine the level of haemolysis, which would have no significant effect on the measurement of cTnT using €˜Roche Modular€™ system.  Before this study, samples were rejected for cTnT analysis when the H index was 35 or when the sample was visibly haemolysed. This resulted in a significant number of samples from A&E patients being rejected.  This was a major clinical issue, especially with a Government target of 98% of A&E patients being seen within 4 hours.

Interference was investigated by mixing pooled serum with known cTnT concentrations containing different concentrations of haemolysate. Haemolysates were prepared by mechanism disruption. The results showed that there was a haemoglobin concentration dependent negative bias in the measurement of cTnT above a haemolysis (H) index of 95 (approximately 1.5 g/L of haemoglobin), which was statistically highly significant (p <0.0001). There was no significant negative bias found below an H index of 95, hence this finding allowed the H index at which samples were rejected for Troponin T analysis to be increased from 35 to 80.  As a consequence the number of urgent A&E samples rejected has been significantly reduced.