Influence of temperature and storage duration on measurement of activated partial thromboplastin time, D‐dimers, fibrinogen, prothrombin time and thrombin time, in citrate‐anticoagulated whole blood specimens

Abstract

We report the effect of temperature and storage duration on a range of haematological analytes: activated partial thromboplastin time (APTT), D-dimers, fibrinogen (Fbg), prothrombin time (PT) and thrombin time (TT). All analytes were measured using a Sysmex CA7000 System with SIEMENS reagents. One hundred and sixty patients were divided into two groups: samples from group A (80 patients) were used to assess the effect of storage at room temperature (RT) (0, 4, 8 and 24 h), and samples from group B (80 patients) were used to determine the effect of storage at 4 °C. Percentage changes compared with baseline results (T = 0 result) were calculated, and clinically relevant differences were defined as a percentage change of >10%. Changes in APTT, D-dimer, Fbg, PT and TT results following 4, 8 and 24 h storage were statistically significant at RT and 4 °C. For D-dimer, Fbg, PT and TT at both RT and 4 °C, the mean percentage changes after all storage periods were <10%, but for APTT, the mean percentage change following 24 h storage was >10% and exceeded the analytical within-batch imprecision. We demonstrate that a storage time interval up to 24 h for D-dimers, Fbg, PT, and TT, and 8 h for APTT at either RT or 4 °C is acceptable.