Influence of In Vitro Hemolysis on 80 Different Laboratory Tests

In vitro hemolysis is probably the most common pre-analytic problem in laboratory medicine. However, it introduces variation into results in unknown ways. Therefore, the purpose of this study was to assess the quantitative effects of hemolysis on 80 different, routine laboratory tests.

We examined the ratio of hemolysis in our hospital from January 1 to March 31, 2015. Next, to study the effect of in vitro hemolysis of whole blood, we added lysed erythrocytes to pooled specimens of serum or plasma to give hemoglobin concentrations of 0.9 to 8.1 g/L and 2.8 to 14 g/L, respectively, and a rating by colorimetry of 0 to 4+ hemolyzed. Then, 80 different laboratory tests were determined with a Hitachi 7700 autoanalyzer for biochemical tests and with AIA 2000, Cobas 6000, and Lumipulus G1200 machines for other tests.

Hemolysis occurred in a total in 8.6% of the specimens in our hospital. Significant correlations with the hemolysis ratio were observed in 43 of 80 laboratory tests. At apparent hemolysis, 11 test levels increased and 7 test levels decreased due to hemolysis. Among the 11 tests, potassium, aspartate aminotransferase, lactate dehydrogenase, thymol turbidity test (TTT), zinc sulfate turbidity test (ZTT), and hyaluronic acid tests showed proportional increases due to hemolysis.

Hemolysis is a common problem for accuracy in many routine laboratory tests. Although the quantitative effects of hemolysis can only be roughly estimated in this report, the approximate extent of change in specific laboratory tests is useful for establishing a baseline for future hemolytic studies.