What is the purpose of a discard tube in phlebotomy?

The purpose of a discard tube in phlebotomy is to avoid contamination of samples. When drawing blood, especially with multiple tubes, the initial blood collected can contain residues or additives from previously used tubes or from the skin or the venipuncture site. Using a discard tube helps to eliminate this potential contamination, ensuring that the blood samples taken afterward are as pure and accurate as possible for testing.

This practice is particularly important when collecting laboratory tests that require pristine samples, such as those for certain chemistry tests where contamination could lead to inaccurate results. The discard tube captures this initial blood, preventing it from affecting subsequent samples intended for specific analyses. Thus, using a discard tube is a critical step in maintaining the integrity of laboratory results.