Which blood samples are drawn first during venipuncture?

The correct choice emphasizes the importance of maintaining sample integrity and avoiding cross-contamination when performing venipuncture. Blood cultures are the first samples drawn because they are highly sensitive to contamination from other blood draw tubes or additives. After blood cultures, the light blue tube is used next, as it contains sodium citrate, which is an anticoagulant. This tube is important for coagulation studies, and it is critical that it is filled properly to maintain the accuracy of the tests.

Following the light blue tube, the red tube can be drawn. This tube is often used for serological tests or tests that do not require anticoagulants. The order of draw is strategically chosen to minimize the risk of carryover from one tube to the next, ensuring each specimen is as pure as possible and the test results are reliable.

In contrast, the other combinations listed do not follow the standards set for the order of draw and can potentially compromise the results of specific tests. Maintaining the proper order is paramount in laboratory practices to ensure accurate and valid test outcomes.