What is the primary purpose of having an order of draw in phlebotomy?

• A. To ensure precise labeling of samples
• B. To prevent cross contamination
• C. To reduce patients' anxiety during blood draws
• D. To increase the speed of sample collection

Answer: (B)

The primary purpose of having an order of draw in phlebotomy is to prevent cross-contamination of different additives present in blood collection tubes. Each type of tube contains specific substances that can alter test results if they mix with those from other tubes. For instance, if a tube containing an anticoagulant is drawn before a serum separator tube, the anticoagulant may contaminate the serum, leading to inaccurate laboratory results. Adhering to a strict order of draw helps maintain the integrity of each sample, ensuring that they can be analyzed reliably.

While aspects such as proper labeling and expediting the drawing process are important in clinical settings, the primary concern with the order of draw is maintaining the scientific accuracy and validity of the tests performed on the collected specimens.