Evaluation of different sized blood sampling tubes for thromboelastometry, platelet function, and platelet count

Abstract Background: To minimise the volume of blood used for diagnostic procedures, especially in children, we investigated whether the size of sample tubes affected whole blood coagulation analyses. Methods: We included 20 healthy individuals for rotational thromboelastometry (RoTEM®) analyses and compared three blood sampling tubes of different size: 1.8, 2.7, and 3.6 mL. All tubes were made of plastic and contained 3.2% sodium-citrate as anticoagulant. Platelet aggregation was investigated in 12 healthy individuals employing the Multiplate® Analyser comparing tubes of 3.6 mL and 1.8 mL. Platelet count was determined for each of the sampling tubes after 10, 60, and 120 min. Results: No significant differences were found in any of the RoTEM® measurements between the three sizes of tubes (p=0.07-0.53). Platelet aggregation was significantly lower when using smaller tubes (p=0.0004). The platelet count remained stable using a 3.6 mL tube during the entire observation period of 120 min (p=0.74), but decreased significantly after 60 min when using tubes smaller than 3.6 mL (p