Which tube in a multiple-tube collection is typically drawn last?

The EDTA tube is used for hematology tests and must be drawn earlier in the sequence to prevent the clotting of blood. Drawing this tube first helps to ensure that the sample remains anticoagulated, which is critical for accurate results in blood cell analyses.

Citrate tubes are used for coagulation studies and are also drawn early in the collection process. This is because they contain anticoagulants that must be introduced to the blood sample as soon as possible to prevent clot formation, which could interfere with the tests being performed.

Blood culture tubes are typically drawn before the serum tube to allow for the identification of pathogens in the blood. They are crucial for microbiological testing and need to be collected first to avoid contamination from other additives present in subsequent tubes.