Prolonged coagulation results are observed in a patient with hematocrit value greater than 55%. What is the appropriate action?

Prolonged coagulation results are observed in a patient with hematocrit value greater than 55%. What is the appropriate action?

• A. Recollect specimen and decrease the amount of anticoagulant
• B. Recollect specimen and increase the amount of anticoagulant
• C. Recollect specimen and decrease the amount of blood
• D. Recollect specimen and increase the amount of blood

Answer: (A)

High hematocrit reduces plasma volume, so the fixed amount of citrate anticoagulant in the collection tube becomes relatively excessive. Citrate binds calcium to prevent clotting, and when the anticoagulant-to-plasma ratio is too high, more calcium is chelated and clotting tests (like PT or aPTT) appear prolonged. The way to correct this is to recollect the specimen with less anticoagulant (use a tube with a lower citrate concentration or less citrate volume) to restore the proper blood-to-anticoagulant ratio. Increasing the anticoagulant would worsen the prolongation, and simply increasing blood without adjusting the anticoagulant would not reliably fix the issue.

High hematocrit reduces plasma volume, so the fixed amount of citrate anticoagulant in the collection tube becomes relatively excessive. Citrate binds calcium to prevent clotting, and when the anticoagulant-to-plasma ratio is too high, more calcium is chelated and clotting tests (like PT or aPTT) appear prolonged. The way to correct this is to recollect the specimen with less anticoagulant (use a tube with a lower citrate concentration or less citrate volume) to restore the proper blood-to-anticoagulant ratio. Increasing the anticoagulant would worsen the prolongation, and simply increasing blood without adjusting the anticoagulant would not reliably fix the issue.