Influence of blood collection technique on platelet function and coagulation variables in dogs.

OBJECTIVE: To investigate the influence of diameter of the catheter and blood collection technique on platelet function and variables reflecting secondary hemostasis, physiologic anticoagulation, and fibrinolysis in dogs. ANIMALS: 6 healthy Beagles. PROCEDURES: Blood samples were collected with 20- and 18-gauge venous catheters immediately after catheters were inserted in a peripheral vein, through a 14-gauge central venous catheter that had been placed via the Seldinger technique in a jugular vein < 30 minutes before sample collection, and through a 13-gauge central venous catheter placed via a catheter-through-the-needle technique < 30 minutes before sample collection (techniques 1 to 4, respectively). Platelet function was assessed in hirudin-anticoagulated whole blood via an impedance-based aggregometer with collagen (0.8, 0.4, 0.2, 0.1, and 0.05 µg/mL) as an inductor. Kaolin-activated thromboelastography variables were determined in citrated whole blood. Prothrombin time, activated partial thromboplastin time, fibrinogen and fibrin D-dimer concentrations, and activity of factor VIII, antithrombin, protein C, and protein S were assessed automatically in citrated plasma. RESULTS: At 0.05 µg of collagen/mL, the highest median rate of aggregation was observed for collection techniques 2 and 3 with 4.3 (range, 2.5 to 6.5) and 3.7 (range, 2.8 to 8.3) aggregation units/min; however, these values were not significantly different from values for the other collection techniques. Generally, sample collection technique did not have a significant impact on results of coagulation variables investigated. CONCLUSIONS AND CLINICAL RELEVANCE: Various blood collection techniques can be used to obtain samples for coagulation testing.