Which anticoagulant is preferred for preserving blood for complete blood count analyses?

Which anticoagulant is preferred for preserving blood for complete blood count analyses?

• A. Sodium citrate
• B. Potassium ethylenediamine tetraacetic acid
• C. Sodium heparin
• D. Sodium fluoride

Answer: (B)

For complete blood counts, keeping the blood from clotting while preserving the integrity and appearance of cells is essential. Potassium EDTA achieves this by chelating calcium, which stops the clotting cascade, so the blood stays as individual cells rather than forming a clot. It also stabilizes cell membranes and minimizes issues like platelet clumping, which helps produce accurate counts and reliable white and red cell indices. Other anticoagulants either dilute the sample (sodium citrate), can alter cell morphology or counts (sodium heparin), or aren’t anticoagulants at all but are used to preserve glucose (sodium fluoride). Because of these effects, potassium EDTA is the preferred anticoagulant for CBC analyses.

For complete blood counts, keeping the blood from clotting while preserving the integrity and appearance of cells is essential. Potassium EDTA achieves this by chelating calcium, which stops the clotting cascade, so the blood stays as individual cells rather than forming a clot. It also stabilizes cell membranes and minimizes issues like platelet clumping, which helps produce accurate counts and reliable white and red cell indices. Other anticoagulants either dilute the sample (sodium citrate), can alter cell morphology or counts (sodium heparin), or aren’t anticoagulants at all but are used to preserve glucose (sodium fluoride). Because of these effects, potassium EDTA is the preferred anticoagulant for CBC analyses.