For the sample type used in evaluating hemolysis effects, which is preferred?

• A. Heparinized plasma
• B. Serum
• C. Whole blood
• D. Urine

Answer: (A)

Hemolysis affects many laboratory measurements because red cell contents spill into the fluid tested, potentially biasing results and altering color. To study how much hemolysis will bias an assay, the most representative testing medium is anticoagulated plasma. Heparinized plasma comes from blood treated with heparin and then separated to yield a stable, unclotted fluid. This setup mirrors how most chemistry tests are performed and allows controlled evaluation of hemolysis effects without the confounding factors that clotting introduces. Serum would reflect elements released during clot formation, which can confound the isolated impact of hemolysis. Whole blood contains intact cells and variable degrees of hemolysis, making it harder to isolate the specific effect of red cell rupture. Urine is not relevant to evaluating hemolysis effects on blood-based assays. Therefore, heparinized plasma is the preferred sample type for this purpose.