ASCP (American Society for Clinical Pathology) Phlebotomy Technician Certification Practice Exam

When a blood specimen tube is not mixed properly after filling, the primary concern is the potential for clot formation. Blood contains various components, including clotting factors, cells, and plasma, which need to be evenly distributed throughout the tube to preserve the integrity of the sample. When the contents are not mixed, the cells can settle at the bottom, leading to separation from the plasma. Additionally, the clotting factors can become more concentrated at the bottom where the cells are, increasing the likelihood of clot development within the tube.

Clots can significantly impact laboratory results, particularly for tests that require serum or plasma, as the presence of clots can lead to inaccurate readings or the necessity to re-collect the sample. Proper mixing is crucial to ensure that additives in the tube, such as anticoagulants in tubes meant for plasma testing, uniformly interact with the blood, preventing clot formation and maintaining sample integrity for accurate analysis.