Which anticoagulant is generally used in coagulation testing and preparing citrated plasma?

Which anticoagulant is generally used in coagulation testing and preparing citrated plasma?

• A. Sodium Citrate
• B. Heparin
• C. EDTA
• D. Oxalate

Answer: (A)

For coagulation testing, you want an anticoagulant that stops clot formation without permanently altering the clotting factors, so the plasma’s ability to clot can be assessed accurately after reintroducing calcium. Sodium citrate does exactly that: it binds calcium ions in the sample, preventing the cascade from proceeding in vitro. This creates citrated plasma that can be used for tests like PT and aPTT, and the effect is reversible—calcium can be restored during the assay to measure the true coagulation potential. Heparin works by inhibiting thrombin and factor Xa, and while it’s useful for some testing, it isn’t the standard for preparing citrated plasma and can interfere with certain coagulation assays. EDTA and oxalate are calcium chelators too, but they’re used for different purposes (EDTA mainly for hematology, oxalate for glucose testing) and they are not suitable for routine coagulation testing because they either alter or irreversibly bind calcium in a way that distorts results.

For coagulation testing, you want an anticoagulant that stops clot formation without permanently altering the clotting factors, so the plasma’s ability to clot can be assessed accurately after reintroducing calcium. Sodium citrate does exactly that: it binds calcium ions in the sample, preventing the cascade from proceeding in vitro. This creates citrated plasma that can be used for tests like PT and aPTT, and the effect is reversible—calcium can be restored during the assay to measure the true coagulation potential.

Heparin works by inhibiting thrombin and factor Xa, and while it’s useful for some testing, it isn’t the standard for preparing citrated plasma and can interfere with certain coagulation assays. EDTA and oxalate are calcium chelators too, but they’re used for different purposes (EDTA mainly for hematology, oxalate for glucose testing) and they are not suitable for routine coagulation testing because they either alter or irreversibly bind calcium in a way that distorts results.