What additive is found in the Purple Tube Top?

The purple tube top, often used in phlebotomy, contains EDTA (Ethylenediaminetetraacetic acid) as its additive. EDTA functions primarily as an anticoagulant, which means it prevents blood from clotting by binding calcium ions in the blood. This property is essential for various hematological tests that require whole blood or plasma, allowing for accurate analysis of blood cell counts and other parameters without interference from clotting.

The use of EDTA is particularly important in tests such as complete blood counts (CBC) where cellular components need to be evaluated. This makes the purple tube ideal for laboratories conducting tests that rely heavily on the characteristics and proportions of blood cells.

Other additives listed, such as sodium citrate, potassium oxalate, and heparin, play different roles and are used in specific types of tests. Sodium citrate is commonly found in blue-top tubes for coagulation studies, potassium oxalate is used in grey-top tubes for glucose testing, and heparin is found in green-top tubes for certain biochemical tests. Each additive serves its purpose based on the requirement of the specific laboratory analysis.