Which tube color is commonly used for CBC testing?

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Multiple Choice

Which tube color is commonly used for CBC testing?

The key idea here is using a blood collection tube that preserves blood cells for an accurate complete blood count. The purple-lavender top tube contains EDTA, an anticoagulant that binds calcium and prevents clotting while keeping red and white cells and platelets intact for counting and morphology. That makes it the standard choice for CBC. Other colors serve different purposes: light blue tubes use sodium citrate for coagulation tests like PT/INR and must be filled to a precise ratio; gold SST tubes contain a clot activator and gel for serum chemistry tests, so they’re not used for CBC; green top tubes have lithium heparin for plasma chemistries and aren’t ideal for CBC because they don’t preserve cells in the same way as EDTA.

The key idea here is using a blood collection tube that preserves blood cells for an accurate complete blood count. The purple-lavender top tube contains EDTA, an anticoagulant that binds calcium and prevents clotting while keeping red and white cells and platelets intact for counting and morphology. That makes it the standard choice for CBC.

Other colors serve different purposes: light blue tubes use sodium citrate for coagulation tests like PT/INR and must be filled to a precise ratio; gold SST tubes contain a clot activator and gel for serum chemistry tests, so they’re not used for CBC; green top tubes have lithium heparin for plasma chemistries and aren’t ideal for CBC because they don’t preserve cells in the same way as EDTA.

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