Which test may yield erroneous results after the phlebotomist redirects the needle several times before entering the vein?

Which test may yield erroneous results after the phlebotomist redirects the needle several times before entering the vein?

• A. CBC
• B. BMP
• C. Glucose
• D. Coagulation

Answer: (D)

The main idea is that pre-analytical handling of blood affects coagulation tests more than other common panels. When a phlebotomist redirects the needle several times, the needle trauma damages the vessel lining and tissue, releasing tissue factor and activating the coagulation cascade. This can alter the sample by causing in vitro clotting or consuming clotting factors, which leads to falsely abnormal results on coagulation studies (like PT/INR and aPTT). Because these tests measure how quickly blood clots and how clotting factors are functioning, they are especially sensitive to such pre-analytical changes. Other tests like CBC, BMP, or glucose are less directly impacted by this kind of local endothelial injury, though they can still be affected by sample quality in other ways. The take-home is that coagulation testing requires careful venipuncture technique to avoid activating the clotting system before the sample is analyzed.

The main idea is that pre-analytical handling of blood affects coagulation tests more than other common panels. When a phlebotomist redirects the needle several times, the needle trauma damages the vessel lining and tissue, releasing tissue factor and activating the coagulation cascade. This can alter the sample by causing in vitro clotting or consuming clotting factors, which leads to falsely abnormal results on coagulation studies (like PT/INR and aPTT). Because these tests measure how quickly blood clots and how clotting factors are functioning, they are especially sensitive to such pre-analytical changes. Other tests like CBC, BMP, or glucose are less directly impacted by this kind of local endothelial injury, though they can still be affected by sample quality in other ways. The take-home is that coagulation testing requires careful venipuncture technique to avoid activating the clotting system before the sample is analyzed.