Pre-analytical variation in the measurements of sensitive markers of coagulation and fibrinolysis: the influence of venipuncture and mixing of blood.

The techniques adopted for venipuncture and the mixing of aspirated blood with anticoagulant were evaluated for their possible contribution in pre-analytical variation in estimating plasma prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT), soluble fibrin and total fibrin(ogen) degradation products. Antecubital vein blood samples were simultaneously collected in 20 subjects from either arm by technologists with high and less blood sampling experience employing a crossover design. F1+2 and TAT were significantly higher in plasma obtained by a less experienced technologist. Three different mixing procedures of blood with anticoagulants did not influence the levels of the markers. The results emphasize that experienced technologists should preferably be selected for collecting blood for analysis of coagulation markers.