Performance of a new rapid test for detecting anti-hepatitis E virus immunoglobulin M in immunocompetent and immunocompromised patients.

BACKGROUND

Hepatitis E virus (HEV) infections are widespread in both developing and developed countries. It is, therefore, important to assess the performance of systems for rapidly detecting anti-HEV immunoglobulin M antibodies in human sera.

OBJECTIVES

To evaluate the diagnostic value of a new immunochromatographic assay, the HEV IgM rapid test (Wantai).

STUDY DESIGN

Blood samples were taken from 30 acutely infected immunocompetent and 30 acutely infected immunocompromised patients, all with HEV RNA in their blood. Specificity and cross reactivity was assessed using samples from 30HEV RNA negative immunocompetent patients who had acute Epstein-Barr virus (EBV) or cytomegalovirus (CMV) infections and 30HEV RNA negative immunocompromised patients. The performance of the HEV IgM Rapid Test was compared to that of a conventional microplate enzyme immunoassay.

RESULTS

The sensitivity of the rapid test in immunocompetent patients was 90% (95% CI: 72.1-100%), similar to that of the Wantai microplate assay (sensitivity: 96.6%, 95% CI: 78.77-100%; p=0.61). The sensitivity of the rapid test in immunocompromised patients was 73.3% (95% CI: 55.4-91.2%) and that of the microplate assay was 83.3% (95% CI: 65.44-100%; p=0.53). The rapid test produced no false positive reactions with samples from HEV RNA negative patients; while the microplate assay gave two false positive results (3.3%).

CONCLUSION

The new Wantai HEV IgM rapid test is easy to use and suitable for rapidly detecting acute hepatitis E infections in both immunocompetent and immunocompromised patients. However, HEV RNA must be detected using a molecular assay for diagnosing an HEV infection in anti-HEV IgM negative patients.