AMCA Phlebotomy Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The correct order of draw when handling blood tests such as Hemoglobin A1C (HA1C) and PT/PTT tests is essential for ensuring accurate test results. For the PT/PTT test, which assesses blood clotting, the appropriate collection tube is typically a light blue top tube that contains sodium citrate as an anticoagulant. This tube must be filled to the appropriate level to maintain the correct blood-to-anticoagulant ratio.

On the other hand, the Hemoglobin A1C test is drawn in a lavender top tube, which contains EDTA as an anticoagulant. This tube is used for hematology tests and does not interfere with the chemistry of the A1C assay.

In the correct sequence, the light blue top tube, used first, is critical to ensure that any coagulation factors are not affected by the presence of other additives that might alter the testing results. Following this with the lavender top tube maintains the integrity necessary for the A1C results, as it avoids any cross-contamination of the blood samples from differing additives.

This specific order helps prevent potential test errors that could arise from additive carryover from one tube type to another, making it crucial for phlebotomists to follow established guidelines to guarantee