Dataset Information

Comparison of a New IgG-EIA for the Detection of Anti-Plasmodium Antibodies with Two Currently Used Assays

ABSTRACT:

Background

Malaria is a mosquito-borne infectious disease caused by protozoan parasites of the genus Plasmodium. As migration of populations from endemic areas to Europe and overseas recreational travel to endemic regions increase, there is also a growing risk of transfusion-transmitted tropical diseases by blood components.

Material and Methods

In the present study two routine Plasmodium spp. ELISA (CAPTIA™ Malaria EIA, Trinity Biotech, and Malaria EIA, BioRad) were compared with a new commercial ELISA (ELISA IgG, EUROIMMUN). From December 1, 2015 until November 30, 2016, 1,096 plasma samples from blood donors with a potential risk of malaria infection were collected at two blood transfusion centres in Germany and Switzerland.

Results

The samples were tested comparatively with the ELISA from EUROIMMUN and the routine test used at the respective centre. Thirty-four of 595 (5.7%) tested blood samples from centre 1 and 49 of 501 (9.8%) tested blood samples from centre 2 showed reactivity on either or both ELISAs. All 83 reactive samples were sent for confirmation to the Diagnostic Centre of the Swiss Tropical and Public Health Institute (Swiss TPH) in Basel, Switzerland. Sixteen samples, which previously were reactive in the routine Plasmodium spp. EIA assays, were proven positive after confirmation testing (i.e., 4 positive and 12 inconclusive results), indicating an anti-Plasmodium antibody prevalence in blood donations of 1.5%. From these 16 reactive samples, 13 were also detected by the index test, resulting in an assay sensitivity of 81.2%. A specificity of 98.6% was calculated (1,065/1,080 confirmed negative samples). The overall agreement with the reference centre was 95.8% in centre 1 and 94% in centre 2.

Conclusion

The comparison of the new EUROIMMUN ELISA and the established CAPTIA™ Malaria EIA (Trinity Biotech) and Malaria EIA (BioRad) used for routine blood donor screening in two laboratory blood donation centres revealed that all tested ELISAs show comparable sensitivities and are equally suitable for anti-Plasmodium antibody screening in blood banks.

SUBMITTER: Niederhauser C

PROVIDER: S-EPMC8578808 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:To enable benchmarking of immunogenicity between candidate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, there is a need for standardized, validated immunogenicity assays. In this article, we report the design and criteria used to validate immunogenicity assays and the outcome of the validation of serologic and functional assays for the evaluation of functional immune response and antibody titers in human serum. A quantitative cell-based microneutralization (MNT) assay, utilizing a reference standard, for detecting anti-SARS-CoV-2 spike protein-neutralizing antibodies in human serum and Meso Scale Discovery's multiplex electrochemiluminescence (MSD ECL) assay for immunoglobulin G (IgG) antibodies to SARS-CoV-2 spike, nucleocapsid, and receptor-binding domain (RBD) proteins were assessed for precision, accuracy, dilutional linearity, selectivity, and specificity using pooled human serum from coronavirus disease 2019 (COVID-19)-confirmed recovered donors. Both assays met prespecified acceptance criteria for precision, relative accuracy, dilutional linearity, selectivity, and specificity. Both assays demonstrated high specificity for the different SARS-CoV-2 antigens or virus tested, and no significant cross-reactivity with seasonal coronaviruses. An evaluation to compare the neutralizing activity in the MNT assay to the IgG measured using the MSD ECL assay showed a strong correlation between the presence of neutralizing activity and amount of antibodies against the spike and RBD proteins in sera from both convalescent and vaccinated individuals. Finally, the MNT assay was calibrated to the WHO reference standard to enable reporting of results in international units, thus facilitating comparison of immunogenicity data generated by different assays and/or laboratories. The MSD ECL assay has previously been calibrated. In conclusion, these validated assays for the evaluation of functional immune response and antibody titers following SARS-CoV-2 vaccination could provide a relatively simple standardized approach for accurately comparing immune responses to different vaccines and/or vaccination regimens.

Project description:Serological assays for SARS-CoV-2 antibodies must be validated for performance with a large panel of clinical specimens. Most existing assays utilize a single antigen target and may be subject to reduced diagnostic specificity. This study evaluated a multiplex assay that detects antibodies to three SARS-CoV-2 targets. Human serum specimens (n = 323) with known previous SARS-CoV-2 exposure status were tested on a commercially available multiplex bead assay (MBA) measuring IgG to SARS-CoV-2 spike protein receptor-binding domain (RBD), nucleocapsid protein (NP), and RBD/NP fusion antigens. Assay performance was evaluated against reverse transcriptase PCR (RT-PCR) results and also compared with test results for two single-target commercial assays. The MBA had a diagnostic sensitivity of 89.8% and a specificity of 100%, with serum collection at >28 days following COVID-19 symptom onset showing the highest seropositivity rates (sensitivity: 94.7%). The MBA performed comparably to single-target assays with the ability to detect IgG against specific antigen targets, with 19 (5.9%) discrepant specimens compared to the NP IgG assay and 12 (3.7%) compared to the S1 RBD IgG assay (kappa coefficients 0.92 and 0.88 compared to NP IgG and S1 RBD IgG assays, respectively. These findings highlight inherent advantages of using a SARS-CoV-2 serological test with multiple antigen targets; specifically, the ability to detect IgG against RBD and NP antigens simultaneously. In particular, the 100.0% diagnostic specificity exhibited by the MBA in this study is important for its implementation in populations with low SARS-CoV-2 seroprevalence or where background antibody reactivity to SARS-CoV-2 antigens has been detected. IMPORTANCE Reporting of SARS-CoV-2 infections through nucleic acid or antigen based diagnostic tests severely underestimates the true burden of exposure in a population. Serological data assaying for antibodies against SARS-CoV-2 antigens offers an alternative source of data to estimate population exposure, but most current immunoassays only include a single target for antibody detection. This report outlines a direct comparison of a multiplex bead assay to two other commercial single-target assays in their ability to detect IgG against SARS-CoV-2 antigens. Against a well-defined panel of 323 serum specimens, diagnostic sensitivity and specificity were very high for the multiplex assay, with strong agreement in IgG detection for single targets compared to the single-target assays. Collection of more data for individual- and population-level seroprofiles allows further investigation into more accurate exposure estimates and research into the determinants of infection and convalescent responses.