A Reference chart for clinical biochemical tests of hemolyzed serum samples

Abstract

Background: Although the effect of hemolysis has been extensively evaluated on clinical biochemical tests, a practical guidance for laboratory staff to rapidly determine whether a hemolyzed blood sample is acceptable and how to interpret the results is lacking. Here, we introduce a chart as a convenient reference for dealing with such samples.

Methods: Serum samples with 0.1%, 0.3%, 1%, 3%, and 10% hemolysis were prepared from sonicated endogenous red blood cells and received 35 wet and 22 dry clinical biochemical tests, respectively. The contributing part in the biochemical test result at each hemolysis condition was derived by subtracting the original test result of this sample with no hemolysis. The net results were used for analyses and preparation of the reference chart.

Results: The reference chart displayed the analytically calculated hemolysis interference and related statistical analyses. The chart also provided the color appearance of serum samples at each hemolysis condition for clinical staffs to determine whether a hemolyzed sample could be accepted.

Conclusion: In clinical laboratories, preparation of such a reference chart is extremely useful in dealing with hemolyzed blood samples for clinical biochemical tests.

Keywords: clinical biochemical test; hemogram test; hemolysis; hemolytic index.

Figure 1

Hemolytic indices following different degrees of hemolysis. A, Demonstration of artificially hemolyzed serum samples. B, Correlations of the hemoglobin concentrations and hemolytic indices with the degrees of hemolysis

Figure 2

Wet biochemistry results under different hemolysis conditions. Samples from three individuals with results were shown. Dashed points and lines were theoretically derived according to previous results. ALB, albumin; ALT, alanine aminotransferase; AMY; amylase; AST, aspartate aminotransferase; CK, creatinine kinase; CREA, creatinine; GLU, glucose; LDH, lactate dehydrogenase; TBIL, total bilirubin; TP, total protein

Figure 3

Dry biochemistry results under different hemolysis conditions. Samples from three individuals with results were shown. Dashed points and lines were theoretically derived according to previous results. ALB, albumin; ALT, alanine aminotransferase; AMY; amylase; AST, aspartate aminotransferase; CK, creatinine kinase; CREA, creatinine; GLU, glucose; LDH, lactate dehydrogenase; TBIL, total bilirubin; TP, total protein

Figure 4

The reference chart of hemolyzed serum samples for clinical chemistry tests. For each analyte, the results of the original sample without the addition of artificially hemolyzed red blood cells (0% hemolysis) were set as the baseline (0.00); the absolute numbers in the table were the increased or decreased part of the results at different hemolysis conditions (0.1%, 0.3%, 1%, 3%, or 10%). The results were the averages of 20 selected samples. One‐way ANOVA (n = 20), linear regression (against H index), and correlation analyses (against H index) were performed (undetectable results were excluded). In the gradient color bars, a half amount of the reference range of each analyte was set for the full colors (eg, for ALT, 22.5 or above was set for the full redness, and −22.5 or below was set for the full blueness). Based on this chart, if a serum sample seems to be about 1% hemolyzed and the ALT test result is 40 U/L, then the true ALT level is likely 37.65 U/L by deducting 2.35 U/L from the test result. “UD” means undetectable. The P values smaller than .05 and r values higher than .995 or lower than −.995 were highlighted in red