Anticoagulant Adjustment

Determine the amount of anticoagulant (in uL) to be removed to adjust for patients with high hematocrit levels.

Formula:

Volume of sodium citrate required = (100 – HCT) / (595 – HCT) x Volume of Whole Blood

Amount to be removed = Volume of citrate in tube – Volume of sodium citrate required

Principle:

Patients with high hematocrit levels greater than 55% have a less than average volume of plasma relative to the total volume of whole blood. This means that the plasma used for coagulation studies will have a higher anticoagulant ratio resulting in a falsely elevated coagulation time. To account for this, some of the anticoagulant from the tube must be removed to maintain ideal anticoagulant ratio.