How do lipemic, hemolyzed, and icteric samples affect test results?

• A. They do not affect color-based assays.
• B. Lipemic, hemolyzed, and icteric samples can bias results by color or turbidity; mitigation includes proper collection and processing.
• C. They always improve accuracy.
• D. Dilution completely eliminates their effect.

Answer: (B)

Interfering substances in a blood specimen can bias test results by altering how light passes through or is absorbed by the sample. When lipids are high, the serum becomes turbid, scattering light and affecting measurements that rely on color or optical clarity. This turbidity can cause some assays to read higher or lower than the true value, depending on the method used. With hemolysis, red blood cells rupture and release hemoglobin and other intracellular contents, coloring the sample and introducing substances that can affect photometric readings and, in some tests, the actual analyte concentrations. Icterus from elevated bilirubin gives a yellow coloration that also absorbs light at the wavelengths used by many colorimetric assays, leading to biased results.

Mitigation centers on proper collection and processing. Ensuring the patient is prepared appropriately (such as fasting if lipemia is a concern), using correct venipuncture technique to avoid hemolysis, and handling and separating specimens promptly helps reduce these interferences. If a sample remains lipemic, hemolyzed, or icteric, labs can use methods like sample clarification (for example, ultracentrifugation to remove lipids) or choose assays less affected by the interference, or adjust the measurement wavelength, and in some cases recollect the specimen. In short, these conditions bias color- and turbidity-based results, and careful collection and processing are key to minimizing their impact.