Which statement best describes the action of citrate in anticoagulation?

Which statement best describes the action of citrate in anticoagulation?

• A. It binds calcium to prevent clotting
• B. It binds iron to prevent clotting
• C. It neutralizes pH to maintain clotting
• D. It promotes platelet clumping

Answer: (A)

Citrate works as an anticoagulant by binding calcium ions. Calcium is a crucial cofactor in many steps of the coagulation cascade, so when citrate sequesters free calcium, the clotting processes can’t proceed and the blood remains liquid. This chelation is why citrate-containing tubes are used for coagulation testing, with calcium able to be reintroduced later to recalcify the sample if needed. Citrate does not bind iron, does not neutralize pH, and does not promote platelet clumping, so those statements don’t describe its action.

Citrate works as an anticoagulant by binding calcium ions. Calcium is a crucial cofactor in many steps of the coagulation cascade, so when citrate sequesters free calcium, the clotting processes can’t proceed and the blood remains liquid. This chelation is why citrate-containing tubes are used for coagulation testing, with calcium able to be reintroduced later to recalcify the sample if needed. Citrate does not bind iron, does not neutralize pH, and does not promote platelet clumping, so those statements don’t describe its action.