Influence of hemolysis on troponin testing: studies on Beckman Coulter UniCel Dxl 800 Accu-TnI and overview of the literature.

Background: Hemolyzed specimens are the leading preanalytical problem in the laboratory practice, and exert a negative impact on test results. We assessed the reliability of Beckman Coulter UniCel Dxl 800 Accu-TnI testing on hemolyzed specimens. Methods: Twelve non-hemolyzed K2EDTA- anticoagulated samples displaying Accu-TnI values >0.20 μg/L and nine with values <0.04 μg/L were selected and three aliquots were obtained from each. The first ("#A") was processed without further manipulation, whereas the second ("#B") and third ("#C") were hemolyzed by aspirating anticoagulated blood through a thin needle. Plasma was separated and tested for hemolysis index (HI) and Accu-TnI. Results: As compared with aliquot #A (HI: 0), a progressive increase of hemolysis occurred in aliquots #B (HI: 25) and #C (HI: 45). The concentration of Accu-TnI gradually decreased from aliquots #A (0.89 μg/L, 0.20-20.16 μg/L), to aliquots #B (0.81 μg/L, 95% CI 0.17-18.37 μg/L; ps0.041) and #C (0.78 μg/L, 95% CI 0.15-17.48 μg/L; ps0.026). In 0/12 (aliquots #B) and 3/12 cases (aliquots #C) the percent decrease exceeded 20% variation. The values remained unchanged in nine samples with Accu-TnI -0.04 μg/L. Conclusions: Accu-TnI values decrease in hemolyzed samples, but the bias might not be clinically significant in samples with hemoglobin