Interference of hemolysis on the postmortem biochemical analysis of IgE by ECLIA

Forensic diagnosis of anaphylactic shock is a challenging task in forensic practice due to the lack of characteristic morphological changes. Postmortem analysis of serum IgE can provide helpful information for determining anaphylaxis. However, postmortem serum always suffers from hemolysis. To investigate the interference of hemolysis on postmortem analysis of total IgE by electrochemiluminescent immunoassay (ECLIA) and verify the suitability of the commercially available ECLIA kit for postmortem hemolyzed blood with the dilution-correction method, different levels of hemolyzed serum were prepared to evaluate the interference of hemolysis. A linear regression analysis was then performed on the concentration of total IgE in the completely hemolyzed blood and the corresponding serum. Our results indicated that hemolysis negatively interfered with the total IgE analysis by ECLIA and the interference (|Bias%|) increased with increasing levels of hemolysis. After controlling for |Bias%| by dilution, the test concentration of total IgE in the completely hemolyzed blood was still significantly lower than that in the serum (P < 0.05) and resulted in eight false-negative cases. A strong correlation was observed between the test concentration of total IgE in the completely hemolyzed blood and that in the serum (r = 0.983). After correction by the regression formula, the corrected concentration revealed no significant differences and exhibited the same diagnostic ability, compared with the serum total IgE concentration. These results indicate that the completely hemolyzed blood is not recommended for postmortem analysis of total IgE directly. The dilution-correction method might have potential utility in forensic practice for evaluating serum total IgE concentrations.