Which anticoagulant is found in a lavender-top blood collection tube?

In lavender-top blood collection tubes, ethylenediaminetetraacetic acid (EDTA) is the anticoagulant used. EDTA works by chelating (binding) calcium ions in the blood. Calcium is essential for the coagulation process, and by removing it from circulation, EDTA effectively prevents clotting. This property makes lavender-top tubes particularly useful for hematology tests, such as complete blood counts (CBC), where the preservation of cellular components is critical for accurate results.

Additionally, the choice of EDTA over other anticoagulants is significant in laboratory settings. For instance, sodium citrate, another common anticoagulant, is typically used for tests that require a different method of clotting assessment, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT). Heparin, a different anticoagulant, is often employed in tests that require plasma, but it can interfere with some specific tests, including hematology analyses. Potassium oxalate is usually found in tubes meant for glucose testing due to its ability to inhibit glycolysis.

The use of EDTA in lavender-top tubes ensures that the samples remain stable for hematology analysis, making it the standard choice for these