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Hepatitis B core antibody screening in a high prevalence group: comparison of three enzyme immunoassays using
H Westh1, S Hoffmann, E Christiansen
1Department of Clinical Microbiology, Rigshospitalet, Copenhagen N Denmark.
Insights
Three enzyme immunoassays for detecting hepatitis B core antibody (anti-HBc) showed high accuracy in homosexual men. Adjusting cut-off values improved agreement between assays to 93%, enhancing hepatitis B infection diagnosis.
Area of Science:
- Hepatology
- Immunology
- Diagnostic Assays
Background:
- Hepatitis B virus (HBV) infection remains a significant global health concern.
- Accurate detection of past or present HBV infection relies on serological markers like the hepatitis B core antibody (anti-HBc).
- Commercially available enzyme immunoassays (EIAs) are widely used for anti-HBc detection.
Purpose of the Study:
- To evaluate and compare the performance of three commercially available anti-HBc EIAs.
- To assess the impact of manufacturer-recommended cut-off values versus modified cut-off values on assay agreement and diagnostic accuracy.
- To determine the optimal cut-off values for enhanced specificity and sensitivity in detecting anti-HBc.
Main Methods:
- Screening of 296 serum samples from homosexual men using three distinct anti-HBc EIAs.
- Classification of patients into non-immune, current, or previous hepatitis B infection categories.
- Calculation of anti-HBc reactivity ratios (sample O.D. x 100 / cut-off O.D.) for performance analysis.
- Receiver operating characteristic (ROC) curve analysis to evaluate assay performance (area under the curve).
Main Results:
- All three EIAs demonstrated high performance with areas under the ROC curve between 96-97%.
- Manufacturer-recommended cut-off values resulted in agreement among the assays for 83% of serum samples.
- Lowering cut-off values (Enzygost EIA to 55%, Enzygost-monoclonal EIA to 85%, Corzyme EIA to 60%) increased assay agreement to 93% with only a marginal loss of sensitivity.
Conclusions:
- The three evaluated anti-HBc EIAs exhibit excellent performance characteristics for diagnosing hepatitis B infection.
- Modifying the cut-off optical density values can significantly improve the concordance between different anti-HBc assays.
- Optimized cut-off values enhance diagnostic accuracy, aiding in the reliable classification of hepatitis B infection status in at-risk populations.
Abstract:
Selected sera from 296 homosexual men were screened by 3 commercially available anti-HBc enzyme immunoassays (EIA). All patients could be classified either as non-immune to hepatitis B, or with current or previous hepatitis B infection. Using the cut-off optical density values (O.D. values) recommended by the respective manufacturers, the results from these three assays were identical for 83% of the serum samples. For anti-HBc reactivity, the ratio (percentage) was calculated using O.D. sample x 100 divided by the O.D. cut-off value. Employing these ratios, sensitivities and specificities for the three assays were compared. All assays performed well when analyzed by receiver operating characteristic curves with area under the curves of 96-97%. A higher specificity, with only a marginal loss of sensitivity could be achieved by lowering the cut-off to 55% for the Enzygost EIA, to 85% for the Enzygost-monoclonal EIA and to 60% for the Corzyme EIA. Using the modified cut-off values, the results with the three assays agreed for 93% of the serum samples.