Agreement between troponin T levels from plain and heparinized tubes

Abstract

Objective: To determine whether there was a clinically significant effect on troponin T measurement when the sample was collected in a heparinized (plasma) blood collection tube compared with a serum tube. Methods: Prospective cohort study using a convenience sample of 198 patients with undifferentiated illness presenting to an Emergency Department who required troponin T measurement. Samples were collected in both plain (serum) tubes and plasma tubes for comparison. All samples were measured using an Elecsys 2010 Immunoassay system (Roche‐Boehringer Mannheim, Germany). Results: There were 35 troponin T measurements ≥ 0.03 µg/L (the limit of reproducibility of the test). The negative predictive value for troponin T performed in heparinized tubes compared with plain tubes was 100% (95% confidence interval 96.4–100) at the ≥ 0.03 µg/L level and 100% (95% confidence interval 97–100%) at the ≥ 0.1 µg/L level. At a cut‐off point for risk stratification in acute coronary syndromes (≥ 0.1 µg/L), there was 100% concordance between the two measurements for each sample. Conclusion: The use of plasma (heparinized) tubes for the collection of troponin T samples is unlikely to produce clinically significant false‐negative results compared with collection of troponin T samples in serum (plain) tubes.

The Feasibility of Using Lithium-Heparin Plasma From a Gel Separator Tube as a Substitute for Serum in Clinical Biochemical Tests

“…Anti-coagulated blood samples are ready to be run once they are drawn from patients. 15 Owning to this time-saving virtue, plasma samples are preferable in urgent tests. Third is the prevention of coagulation-induced interferences.…”