Influence of needle gauge used for venipuncture on automated platelet count and coagulation profile in dogs

Objective To determine if differing gauge ( G ) needles used for venipuncture altered the automated platelet count and coagulation profile (prothrombin time ( PT ) and activated partial thromboplastin time (a PTT )) in clinically healthy dogs. Design Prospective, observational, randomised, clinical study. Methods We enrolled 20 clinically healthy dogs. Blood was collected via direct venipuncture of the jugular veins with 21 G , 23 G and 25 G needles in a random order. Automated haematology and automated coagulation times were performed on the blood samples. Values were analysed for differences among the needle gauges and also the order of sample collection. Results No difference was found in the automated platelet count or automated coagulation times for the three needle gauges used or the order in which the samples were collected. Conclusion Venipuncture can be performed with a 21 G , 23 G or 25 G needle to obtain blood from dogs for automated platelet count and PT/aPTT measurement without affecting the results.