What is the most common complication of phlebotomy?

• A. Hematoma
• B. Petechiae
• C. Thrombosis
• D. Infection

Answer: (A)

The main idea here is understanding what commonly goes wrong after taking a blood sample. A hematoma forms when blood leaks from the punctured vein into the surrounding tissue, creating a bruise or swelling at the site. This is the most frequent complication in phlebotomy because even with careful technique, small vessels can bleed a bit into the tissue, especially if pressure isn’t applied long enough after removing the needle, the tourniquet was left on too long, or the vein is difficult to access. Proper technique—stabilizing the vein, inserting the needle with the bevel up, and applying firm pressure for several minutes after withdrawal—greatly reduces the risk of a hematoma.

Petechiae are tiny spots caused by capillary fragility or platelet issues and, while possible, are less common in routine venipuncture. Thrombosis (a clot in the vein) and infection are rarer complications when proper aseptic technique is used. Thus, the scenario most frequently encountered is the hematoma.