What additive is present in a lavender top blood collection tube?

The lavender top blood collection tube contains EDTA (ethylenediaminetetraacetic acid) as its additive. EDTA is an anticoagulant that effectively chelates calcium ions, thus preventing blood from clotting when collected in this type of tube. This characteristic makes it particularly useful for hematological tests, as it preserves the cellular components of the blood for accurate analysis.

This choice is commonly used in laboratory settings for complete blood counts (CBCs) and other tests where the preservation of blood cells is critical. The lavender top tube's design specifically accommodates the need for blood samples that require anticoagulation without causing clotting.

Other options represent different additives that function in unique ways. Sodium citrate is used for coagulation studies, lithium heparin is typically found in green top tubes and is used for plasma tests, while serum separator gel is used in gold or red top tubes for serum tests but does not serve the anticoagulant purpose fulfilled by EDTA in lavender tubes.