Lavender-top tubes with EDTA serve what primary function in hematology testing?

Lavender-top tubes with EDTA serve what primary function in hematology testing?

• A. Chelates calcium to prevent clotting; preserves cellular elements for CBC.
• B. Activates platelets to speed clotting.
• C. Stabilizes bilirubin for liver function testing.
• D. Prevents hemolysis of samples during handling

Answer: (A)

The main idea here is that EDTA in lavender-top tubes acts as an anticoagulant by binding calcium, which is essential for the blood clotting cascade. By removing calcium, the blood stays in a liquid state, allowing the cells to be preserved in their native form for accurate counting and morphology assessment in a complete blood count. This preservation of cellular elements is what makes EDTA the go-to additive for hematology testing. The other options don’t fit because they describe functions that EDTA does not perform. It does not activate platelets or accelerate clotting; in fact, it prevents clotting. It doesn’t stabilize bilirubin for liver tests, which requires different reagents or handling. And while minimizing hemolysis is important, EDTA’s primary role is anticoagulation, not preventing hemolysis during handling.

The main idea here is that EDTA in lavender-top tubes acts as an anticoagulant by binding calcium, which is essential for the blood clotting cascade. By removing calcium, the blood stays in a liquid state, allowing the cells to be preserved in their native form for accurate counting and morphology assessment in a complete blood count. This preservation of cellular elements is what makes EDTA the go-to additive for hematology testing.

The other options don’t fit because they describe functions that EDTA does not perform. It does not activate platelets or accelerate clotting; in fact, it prevents clotting. It doesn’t stabilize bilirubin for liver tests, which requires different reagents or handling. And while minimizing hemolysis is important, EDTA’s primary role is anticoagulation, not preventing hemolysis during handling.