Quality Control, Equipment Logs and Waived Tests

Quality Assurance and the Pre-Analytical Phase

Quality assurance encompasses continuous programs and policies designed to ensure excellence across all phases of laboratory testing. Laboratory work is divided into three distinct phases: pre-analytical, analytical, and post-analytical. The phlebotomist's primary clinical duties occur within the pre-analytical phase. This phase covers every step that occurs before actual testing begins, from verifying the patient to preparing the sample. Because specimen integrity is essential to accurate testing, the phlebotomist plays a foundational role in preventing errors; analytical and post-analytical processes also affect accuracy.

A core quality assurance standard is verifying at least two unique patient identifiers before blood collection. Once the draw is complete, the phlebotomist must label each specimen immediately in the patient's presence and before leaving the collection area, following facility policy. Technical collection steps also require strict adherence: following the standardized order of draw minimizes the risk of additive carryover between tubes, and gently inverting additive tubes immediately after collection as directed by the manufacturer mixes the additive and reduces the risk of clot formation.

Key pre-analytical quality indicators include patient identification accuracy, specimen labeling accuracy, and proper tube fill volume. An underfilled tube may be rejected as quantity not sufficient (QNS), depending on the test, tube requirements, and laboratory policy; report the problem and follow instructions for recollection. Hemolysis, another common pre-analytical error, ruptures red blood cells and falsely elevates analytes such as potassium and lactate dehydrogenase. Facilities also monitor blood culture contamination rates as a quality indicator; phlebotomists must follow their facility's current target rather than assuming a universal threshold of less than 3%. Turnaround time is another tracked quality metric, measured from a defined starting point, such as specimen collection or laboratory receipt, to result availability.

Special handling procedures protect vulnerable analytes before they reach the testing bench. For example, exposing light-sensitive specimens, such as bilirubin, to ambient light is a pre-analytical error that degrades test results. Similarly, specimens requiring chilled handling, such as ammonia when specified by the laboratory, must be transported according to test instructions. Any delay or improper handling must be reported directly to the nurse or supervisor.