What is the purpose of the lavender top tube?

The lavender top tube is specifically used for hematology tests, most notably for a complete blood count (CBC). This type of tube contains an anticoagulant called EDTA, which is crucial for preventing blood from clotting. When performing a CBC, it's essential that the blood remains in a liquid state to allow accurate counting of various blood components, such as red blood cells, white blood cells, and platelets.

Hematology tests require whole blood rather than serum, making the vacuum-sealed environment of the lavender top tube ideal for preventing clotting and preserving the cellular components necessary for these evaluations. Consequently, the use of the lavender top tube is integral to obtaining reliable and valid test results in hematology.

The other options pertain to different types of laboratory tests that use other colored top tubes which are not suited for hematology analysis.