For malarial blood smears prepared from venous blood, which anticoagulant is preferred?

For malarial blood smears prepared from venous blood, which anticoagulant is preferred?

• A. Sodium fluoride
• B. EDTA
• C. Sodium citrate
• D. Heparin

Answer: (B)

For malarial blood smears, you want an anticoagulant that prevents clotting without distorting the cells or the parasites. EDTA achieves this by binding calcium and stopping coagulation, while preserving red blood cell morphology and the appearance of Plasmodium species so they stain clearly with Giemsa or other Romanowsky stains. This makes it the most reliable choice for accurate microscopic detection. Sodium fluoride isn’t an anticoagulant for smear preparations (it’s a glycolysis inhibitor used for glucose testing). Sodium citrate is an anticoagulant but can cause some morphological changes in blood films that may affect parasite visualization. Heparin can also alter smear appearance and background staining, potentially complicating parasite detection.

For malarial blood smears, you want an anticoagulant that prevents clotting without distorting the cells or the parasites. EDTA achieves this by binding calcium and stopping coagulation, while preserving red blood cell morphology and the appearance of Plasmodium species so they stain clearly with Giemsa or other Romanowsky stains. This makes it the most reliable choice for accurate microscopic detection.

Sodium fluoride isn’t an anticoagulant for smear preparations (it’s a glycolysis inhibitor used for glucose testing). Sodium citrate is an anticoagulant but can cause some morphological changes in blood films that may affect parasite visualization. Heparin can also alter smear appearance and background staining, potentially complicating parasite detection.