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Appak Ö, Gülmez A, Güzel I, Gezer NS, Doruk ÖG, Ergor OA, Esen N, Sayıner AA. Evaluation of COVID-19 antibody response with using three different tests. IJM 2021; 13:565-573. [PMID: 34900153 PMCID: PMC8629824 DOI: 10.18502/ijm.v13i5.7417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background and Objectives: In this study, the performance of three different commercial antibody assays for COVID-19 was examined and parameters affecting the antibody response were investigated. The correlation of patients’ chest CT results, procalcitonin, CRP, and D-dimer levels with the antibody response were retrospectively evaluated.
Materials and Methods: COVID-19 antibodies were detected by three commercially available assays in each patient. Two of the assays were rapid immunochromatographic tests and - one was an ELISA-based IgG assay. SARS-CoV-2 RNA was tested by “COVID-19 RT-qPCR Detection Kit” using nasopharyngeal swab samples. The results of antibody tests were com- pared with each other, RT-qPCR, Biochemical parameters and chest CT findings.
Results: RT-qPCR was positive in 46.6% (41/88) of the evaluated patients among which 77.3% (68/88) were healthcare workers. Seventeen (41.4%) of viral RNA positive patients had a positive antibody result with at least two assays. Both of the rapid immunochromatographic tests had identical sensitivity of 36.6% and specificity of 100%, compared to RT-qPCR assay; while the sensitivity of the ELISA based Euroimmune test was 43.9%, and the specificity was 95.7%. The sensitivity and specificity of the immunochromatographic tests were 75% and 100% respectively, compared to ELISA test result. There was a correlation between antibody positivity and old age and male gender. The presence of typical chest CT findings increased the antibody positivity 13.62 times. Antibody positivity was also increased with the decrease in Ct value of the PCR assay. There was no significant relationship between the biochemical parameters (CRP, D-dimer and procalcitonin values) and the antibody or RT-qPCR results.
Conclusion: There was a correlation between antibody response and male gender, older age, presence of symptoms, typical chest CT findings and low PCR-Ct value.
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Affiliation(s)
- Özgür Appak
- Department of Medical Microbiology, Division of Medical Virology, School of Medicine, Dokuz Eylul University, Izmir, Turkey
- Corresponding author: Özgür Appak, Ph.D, Department of Medical Microbiology, Division of Medical Virology, School of Medicine, Dokuz Eylul University, Izmir, Turkey. Tel: +90-5333141093
| | - Abdurrahman Gülmez
- Department of Medical Microbiology, Istanbul Basaksehir Cam ve Sakura Hospital, Istanbul, Turkey
| | - Irmak Güzel
- Department of Medical Microbiology, School of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Naciye Sinem Gezer
- Department of Radiology, School of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Özlem Gürsoy Doruk
- Department of Medical Biochemistry, School of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Osman Alparslan Ergor
- Department of Public Health, School of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Nuran Esen
- Department of Medical Microbiology, School of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Ayca Arzu Sayıner
- Department of Medical Microbiology, Division of Medical Virology, School of Medicine, Dokuz Eylul University, Izmir, Turkey
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