Processing After the specimens have been correctly identified and labeled, the samples move on to processing. Some samples need to have their cellular elements separated from their plasma or serum by centrifugation. Chemistry and Coagulation tests are not accurate for diagnosing disease if cellular elements or their contents are present in the blood. Incomplete processing of coagulation tubes leaves the platelets in the plasma, lowering the PTT times and giving inaccurate results. When red cells hemolyze or break open, they contaminate the plasma with enzymes and potassium.
Hemolysis is caused by traumatizing the thin membraned red cells.
Frequently this is due to using a small bore needle to draw the blood. That small bore causes the red cells to tumble violently when the syringe is pulled back or the blood enters the vacuum tube. The fragile cell membranes rip open and the cellular contents spill out into the plasma. As laboratory professionals it is our responsibility to ensure that the patient receives quality care by insisting that we obtain a quality sample free from hemolysis or other contaminates such as IV fluid.