When performing venipuncture, which tube should be drawn after obtaining blood cultures?

The correct choice is the light blue tube following the collection of blood cultures during a venipuncture procedure. Blood cultures are typically collected first to ensure that there is no contamination from additives present in other tubes that may affect the growth of microorganisms.

After blood cultures, the light blue tube is drawn next because it is used for coagulation tests, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT). This tube contains sodium citrate, an anticoagulant that helps preserve the blood for accurate testing.

When preparing for venipuncture, it is essential to follow the correct order of draw to maintain the integrity of the samples. Drawing the light blue tube at this point, after blood cultures, is in accordance with practices that help prevent cross-contamination and ensures the reliability of subsequent lab tests.

Other types of tubes, such as the red, green, or lavender ones, contain different additives meant for serum, chemistry, and hematology tests. Drawing these tubes before the light blue could introduce substances that interfere with coagulation studies. Therefore, the light blue tube is the appropriate choice to follow blood cultures.