Which blood collection tube prevents contamination during the draw?

The discard tube is designed specifically to prevent contamination during the collection of blood samples. It is typically used at the beginning of a collection sequence, particularly in cases where certain blood collection protocols require that the first tube be discarded. This is particularly important for tests that could be influenced by contaminants in the blood, such as those from the skin or from previous samples. Using a discard tube helps to clear the line of potential contaminants, ensuring that subsequent samples collected in other tubes will be more reliable and accurate for testing purposes.

Other tubes like sodium citrate, lavender, and serum separator tubes serve specific functions in the collection and processing of blood and are not primarily intended to prevent contamination during the draw. For example, sodium citrate is mainly used for coagulation tests, while the lavender tube is typically used for hematology tests. The serum separator tube is used when serum is required for testing but does not have the same focus on contamination prevention at the start of a blood draw.