Furthermore, since K3 EDTA is a liquid, it could have a dilutional effect on small sample volumes. (E.g., a 0.5 mL blood sample having a hematocrit of 40 is collected in a 5 mL Vacutainer containing the usual 20 mLs of K3 EDTA. The plasma volume = (0.5 mL * ((100-40)/100)) = 0.3 mLs.