Which specimen would be considered unsuitable?

In laboratory testing, the quality and characteristics of specimens are crucial for obtaining reliable results. Plasma or serum that appears abnormal may indicate potential issues such as hemolysis, lipemia, or the presence of particulate matter, which can affect test outcomes.

In this scenario, a PST (Plasma Separation Tube) containing red-colored plasma is deemed unsuitable. The red color typically indicates the presence of hemolysis, where red blood cells have broken down and released hemoglobin into the plasma. Hemolysis can interfere with various laboratory tests, leading to inaccuracies in results, such as altered electrolyte levels, falsely elevated enzyme readings, or issues with other biochemical tests.

In contrast, clear plasma from a PST tube suggests that the specimen is free from hemolysis, while straw-colored plasma in an EDTA tube indicates normal plasma consistency without sediment or particles. A cloudy serum from an SST (Serum Separator Tube) can also indicate lipemia, but it may still be acceptable for certain tests depending on the laboratory’s protocols. However, red-colored plasma points directly to a problem with the sample’s integrity, making it unsuitable for testing.