Short-term venous stasis influences routine coagulation testing.

Preanalytical variability is a common source of errors in coagulation testing, as clotting assays are particularly susceptible to poor standardization of the whole analytical process. To investigate the effect of a short-term venous stasis on routine coagulation testing, we measured activated partial thromboplastin time, prothrombin time, fibrinogen and D-dimer in plasma specimens collected either without venous stasis or following the application of a 60 mmHg constant, standardized external pressure by a sphygmomanometer, for 1 (1-min stasis) and 3 min (3-min stasis). When compared with blood specimens collected without stasis, the Pearson's correlation coefficients and the corresponding slopes of the Passing and Bablok regression line of samples collected following 1 and 3-min stasis were acceptable. However, statistically significant differences by paired Student's t-test could be observed for all parameters tests following 3-min stasis, and for all but the activated partial thrombo...