What do lavender-top tubes contain, and what are they used for?

Lavender-top tubes contain EDTA (ethylenediaminetetraacetic acid), which is an anticoagulant that prevents blood from clotting. This property makes the lavender-top tube particularly valuable for hematology tests, where the accurate analysis of blood cells, such as complete blood counts (CBC), requires whole blood samples without coagulation. The preservation of the blood's cellular components is crucial for accurate results in these kinds of assays.

In contrast, other options mention substances and uses that are not associated with lavender-top tubes. For instance, heparin is found in green-top tubes and is used for various tests, including some that measure blood chemistry. Sodium citrate is used in light blue-top tubes, primarily for coagulation studies. Lastly, serum, which is obtained from blood that has clotted and then centrifuged, is typically collected in red-top or marble-top (gold or tiger-striped) tubes and is used for serum chemistry tests. Understanding the specific properties and appropriate usage of blood collection tubes is essential for ensuring the accuracy of laboratory tests.