Comparing Assay Performance of ELISA and Chemiluminescence Immunoassay in Detecting Antibodies to Hepatitis B Surface Antigen

INTRODUCTION

Antibodies to Hepatitis B surface Antigen (Anti-HBs) levels are measured as markers for immune response to vaccination and in decision making for post-exposure prophylaxis against Hepatitis-B. Several immunoassay formats are used to measure Anti-HBs, thus carrying the possibility of variation in measured levels between different assays. This study compares the performance of Chemiluminescence Immunoassay (CLIA) against Enzyme-linked Immunosorbent Assay (ELISA) in measuring Anti-HBs titer by looking into concordance between the two test reports.

AIM

To compare the agreement between ELISA and CLIA in measurement of Anti-HBs antibody titers.

MATERIALS AND METHODS

This prospective comparative study conducted at Kasturba Medical College, Manipal measured consecutive serum samples (69) sent for anti-HBs levels during May-June 2016 using both CLIA (Abbott Architect) and ELISA (Bio-Rad). Anti-HBs values of ≤10mIU/ml was considered as non-protective and >10mIU/ml as protective. The agreement between the tests in classifying the antibody titers as non-protective or protective was computed using Kappa coefficient, and the difference in individual titer values between the tests compared using Bland-Altman plot on SPSS (v.15).

RESULTS

Out of the 69 samples analysed, 18 samples (26.1%) were of health-care personnel and remaining of patients. Agreement between ELISA and CLIA in identifying the antibody titers as protective and non-protective were 96.5% and 90.9% respectively, resulting in an agreement of 0.84. The coefficient-of-variation of ELISA and CLIA were 74.5% and 113.1%, respectively. Three value based discordant results were noted; two samples deemed protective by ELISA were reported as non-protective by CLIA. One non-protective titer by ELISA was reported as protective by CLIA.

CONCLUSION

Analytical agreement is good between the two immunoassays. However there are some discrepancies in quantitative measurement. This may have been due the variation in the standard calibrators used in each assay. Though CLIA showed more variation in the values, it has the advantage of being automated test with low turn around time. Therefore, both the test methodologies can be reliably used in place of each other for detection of Anti- HBs titer.

Development and Implementation of Autoverification Rules for ELISA Results of HBV Serological Markers

Autoverification is a process of using computer-based rules to verify clinical laboratory test results without manual review. But to date, there are few published articles on the use of autoverification over the course of years in a clinical laboratory. In our study, we firstly described the development and implementation of autoverification rules for enzyme-linked immunosorbent assay (ELISA) results of hepatitis B virus (HBV) serological markers in a clinical immunology laboratory. We designed the autoverification rules for HBV by using Boolean logic on five clinically used serological markers in accordance with the framework of AUTO-10A, issued by the American Clinical Laboratory Standards Institute in 2006. The rules were written into the laboratory information system (LIS) and installed in the computer, so we could use the LIS to screen the test results. If the results passed the autoverification rules, they could be sent to doctors immediately. To evaluate the autoverification rules, we applied the real-time data of 11,585 patients with the autoverification rules. The autoverification rate of the five HBV serological markers was 79.5%. Furthermore, the turnaround time (TAT) was reduced by 38% (78 minutes vs. 126 minutes). The error rate was nearly eliminated. These results show that using LIS with autoverification rules can shorten TAT, enhance efficiency, and reduce manual review errors.

A rapid and sensitive method based on magnetic beads for the detection of hepatitis B virus surface antigen in human serum

Current clinically assays, such as enzyme-linked immunosorbent assay and chemiluminescence immunoassay, for hepatitis B surface antigen (HBsAg) are inferior in terms of either sensitivity and accuracy or rapid and high-throughput analysis. A novel assay based on magnetic beads and time-resolved fluoroimmunoassay was developed for the quantitative determination of HBsAg in human serum. HBsAg was captured using two types of anti-HBsAg monoclonal antibodies (B028, S015) immobilized on to magnetic beads and detected using europium-labeled anti-HBsAg polyclonal detection antibody. Finally, the assay yielded a high sensitivity (0.02 IU/mL) and a wide dynamic range (0.02-700 IU/mL) for HBsAg when performed under optimal conditions. Satisfactory accuracy, recovery and specificity were also demonstrated. The intra- and interassay coefficients of variation were 4.7-8.7% and 3.8-7.5%, respectively. The performance of this assay was further assessed against a well-established commercial chemiluminescence immunoassay kit with 399 clinical serum samples. It was revealed that the test results for the two methods were in good correlation (Y = 1.182X - 0.017, R = 0.989). In the current study, we demonstrated that this novel time-resolved fluoroimmunoassay could be used: as a highly sensitive, automated and high-throughput immunoassay for the diagnosis of acute or chronic hepatitis B virus infection; for the screening of blood or organ donors; and for the surveillance of persons at risk of acquiring or transmitting hepatitis B virus.

Distribution Characteristics of Hepatitis B Serological Markers in Hospitalized Children and Adolescents in Zhejiang, China between 2006 and 2010

Background/Aims

To investigate serological patterns of hepatitis B based on electrochemiluminescent immunoassays and the distribution characteristics of these patterns in hospitalized children and adolescents in Zhejiang, China between 2006 and 2010.

Methods

Five serological markers, including hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), antibody to hepatitis B surface antigen (anti-HBs), antibody to hepatitis B e antigen (anti-HBe), and antibody to hepatitis B c antigen (anti-HBc), were chosen as a routine panel to monitor hepatitis B virus (HBV) infection and vaccination efficacy. A total of 33,187 children (21,187 boys and 12,000 girls) were selected using the following exclusion criteria: a previous diagnosis of hepatitis, age >16 years or an address outside of Zhejiang.

Results

The average HBV vaccination coverage rates among 20,766 boys and 11,782 girls were 98.62% and 98.68%, respectively. Seventeen serological patterns of hepatitis B were found, and the dominant pattern was 'anti-HBs (+) alone' (62.03%) followed by 'negative pattern' (23.46%). The rates of the other 15 patterns ranged from 8.14% to 0.003%. Of 236 HBsAg-positive patients, the overall rate of seropositivity was 0.71%. The anti-HBs levels were grouped into 3 ranges (10-100 mIU/mL, 100-1,000 mIU/mL, and >1,000 mIU/mL) for all anti-HBs-positive children (36.08%, 43.43%, and 20.49%, respectively).

Conclusions

A low HBsAg carrier rate and a relatively high anti-HBs positive rate are present in hospitalized children and adolescents in Zhejiang. The distribution of serological patterns is associated with age but is mostly independent of gender.

[Comparison of nine different qualitative HBsAg assay kits]

BACKGROUND

Qualitative hepatitis B surface antigen (HBsAg) assay kits are still commonly used in Korea where hepatitis B virus (HBV) infection is endemic. The accurate determination of HBsAg plays a crucial role in the diagnosis and prevention of HBV infection, especially in endemic areas. The aim of this study was to compare the detection sensitivities of 9 qualitative HBsAg assay kits.

METHODS

Seven pooled sera with HBsAg concentration ranging from 0.14 IU/mL to 29.96 IU/mL were prepared. The HBsAg concentration of each pooled serum was determined by a quantitative HBsAg assay, Architect HBsAg (Abbott Laboratories, Ireland). The fully automated immunoassay kits included Elecsys HBsAg (Roche Diagnostics, Germany) and Immulite 2000 HBsAg (DPC, USA) and the rapid tests included 5 immunochromatographic assay (ICA) kits and 2 reverse passive hemagglutination assay (RPHA) kits.

RESULTS

Elecsys HBsAg (Roche Diagnostics) showed positive result in pooled serum with HBsAg concentration of 0.14 IU/mL, but Immulite 2000 HBsAg (DPC) showed negative result in the same concentration. Although ICA kits showed variable results among different assay kits, all of them showed negative results in pooled sera with HBsAg concentration of < or = 1.89 IU/mL. Two RPHA kits showed negative results in pooled sera with HBsAg concentration of < or = 7.98 IU/mL.

CONCLUSIONS

Although ICAs were more sensitive than RPHAs, they had variable sensitivities for HBsAg and were less sensitive than the automated immunoassay kits. Therefore, ICAs and RPHAs should be used with caution in the screening tests for HBsAg and their sensitivities need to be improved.