Final answer:
Lavender or pink colored tubes are typically used to contain EDTA for preventing blood clotting during tests such as CBC. They allow for accurate cell counts as EDTA binds calcium, which is necessary for coagulation.
Step-by-step explanation:
The color of the tube that typically contains EDTA as an anticoagulant is lavender or sometimes pink. EDTA (Ethylenediaminetetraacetic acid) is added to these tubes to chelate (bind) calcium ions, thus preventing blood clotting which makes it suitable for hematological tests. EDTA works by binding to the calcium in the blood and is often used when blood is collected for CBC (Complete Blood Count) tests or blood smears, as it preserves the shape of cells and platelets, giving an accurate count. In the context of plasma preparation, blood is collected into these EDTA-containing tubes and centrifuged to obtain plasma. Sometimes, other substances like ACN (Acetonitrile) containing the IS (Internal Standard) are added to help in further analysis.