RESUMO
Objective To assess the differences in the specificity and the sensitivity in detecting specific IgM by indirect ELISA and capturing-ELISA methods,and to analyze the possible causes of those differences.Methods The HBc-IgM and EHF-IgM level in serum samples from activity Hepatitis B patients and hemorrhagic fever patients with renal syndrome were determined by both indirect-ELISA and capturing-ELISA methods,and the differences in the positive rate,positive threshold value and the specificity between those two methods were compared. Results Specific murine IgM diluted in PBS were detected by indirect-ELISA and capturing-ELISA,and the specificity and sensitivity of those two methods were similar.Results showed that sensitivity of indirect-ELISA was lower than capturing-ELISA in detecting specific IgM in serum from patients with activity Hepatitis B and hemorrhagic fever patients with renal syndrome.The IgM level in hepatitis B and hemorrhagic group treated with thioglycol became negative detected by those two methods,suggesting that both of them have the anti-IgM epitope-specificity.Cross reaction results demonstrated that the reagent detecting IgM from the two methods had the specificity to the specific antigen. Conclusion It is recommended to detect IgM level by capturing-ELISA method for the early diagnosis of acute infectious disease,pathological changes,immune reaction and prognoses of chronic continuous infectious disease.Applying the indirect-ELISA method to detect IgM level to diagnose acute infectious disease is to discuss in the future.