Evaluation of two SARS-CoV-2 immunoassays
| dc.contributor.advisor | Hardie, Diana | |
| dc.contributor.author | Naidoo, Michelle | |
| dc.date.accessioned | 2023-03-31T07:34:23Z | |
| dc.date.available | 2023-03-31T07:34:23Z | |
| dc.date.issued | 2022 | |
| dc.date.updated | 2023-03-31T07:33:39Z | |
| dc.description.abstract | Aim: The purpose of this study is to verify the performance of the Roche Elecsys ® antinucleocapsid (qualitative) and anti-spike (quantitative) SARS-CoV-2 immunoassays to determine whether the performance of the assays is acceptable for diagnostic use in the Groote Schuur Hospital virology/chemistry laboratory, as well as other National Health Laboratory Service (NHLS) laboratories in South Africa. Methods: We performed a verification study using de-identified remnant serum or plasma samples. Standard verification experiments including sensitivity, specificity and precision were performed. Pre-pandemic samples were used to assess specificity. Samples with a linked positive SARS-CoV-2 polymerase chain reaction (PCR) result on a respiratory sample >10 days before the serum/plasma collection date were used to assess sensitivity. Additionally, postvaccine humoral response and other parameters was assessed in a cohort of laboratory staff. Results: For the anti-nucleocapsid antibody assay, specificity was 99.7% based on 316 samples and sensitivity 91.3% based on 404 samples. For the anti-spike antibody assay, the specificity based on 194 samples was 100%, and the sensitivity based on 384 samples was 93.8%. Both assays demonstrated acceptable precision. Furthermore, the anti-spike antibody assay sensitivity was >92% during the first three waves in South Africa, dominated by different SARS-CoV-2 variants. Post-vaccine seroconversion in 115 staff with no evidence of prior natural infection was 99% and hybrid immunity produced higher anti-spike antibody titres compared to vaccine-only participants. Conclusion: Both immunoassays met our acceptance criteria. Both assays can be used for seroprevalence studies. The anti-nucleocapsid immunoassay assay is valuable in confirming past natural infection in patients with previous asymptomatic infection, previous symptomatic infection where no PCR was done or PCR-negative patients who present to hospital with COVID-19 during the second week of illness or later. Most importantly, the antispike immunoassay can be used as a reliable, cheap, and easily accessible surrogate marker of post-vaccine humoral immune response and we recommend using this to confirm and monitor humoral immune response in patients with risk factors for non-seroconversion following vaccination and increased risk for morbidity and mortality following infection with SARS-CoV-2. | |
| dc.identifier.apacitation | Naidoo, M. (2022). <i>Evaluation of two SARS-CoV-2 immunoassays</i>. (). ,Faculty of Health Sciences ,Department of Clinical Laboratory Sciences. Retrieved from http://hdl.handle.net/11427/37603 | en_ZA |
| dc.identifier.chicagocitation | Naidoo, Michelle. <i>"Evaluation of two SARS-CoV-2 immunoassays."</i> ., ,Faculty of Health Sciences ,Department of Clinical Laboratory Sciences, 2022. http://hdl.handle.net/11427/37603 | en_ZA |
| dc.identifier.citation | Naidoo, M. 2022. Evaluation of two SARS-CoV-2 immunoassays. . ,Faculty of Health Sciences ,Department of Clinical Laboratory Sciences. http://hdl.handle.net/11427/37603 | en_ZA |
| dc.identifier.ris | TY - Master Thesis AU - Naidoo, Michelle AB - Aim: The purpose of this study is to verify the performance of the Roche Elecsys ® antinucleocapsid (qualitative) and anti-spike (quantitative) SARS-CoV-2 immunoassays to determine whether the performance of the assays is acceptable for diagnostic use in the Groote Schuur Hospital virology/chemistry laboratory, as well as other National Health Laboratory Service (NHLS) laboratories in South Africa. Methods: We performed a verification study using de-identified remnant serum or plasma samples. Standard verification experiments including sensitivity, specificity and precision were performed. Pre-pandemic samples were used to assess specificity. Samples with a linked positive SARS-CoV-2 polymerase chain reaction (PCR) result on a respiratory sample >10 days before the serum/plasma collection date were used to assess sensitivity. Additionally, postvaccine humoral response and other parameters was assessed in a cohort of laboratory staff. Results: For the anti-nucleocapsid antibody assay, specificity was 99.7% based on 316 samples and sensitivity 91.3% based on 404 samples. For the anti-spike antibody assay, the specificity based on 194 samples was 100%, and the sensitivity based on 384 samples was 93.8%. Both assays demonstrated acceptable precision. Furthermore, the anti-spike antibody assay sensitivity was >92% during the first three waves in South Africa, dominated by different SARS-CoV-2 variants. Post-vaccine seroconversion in 115 staff with no evidence of prior natural infection was 99% and hybrid immunity produced higher anti-spike antibody titres compared to vaccine-only participants. Conclusion: Both immunoassays met our acceptance criteria. Both assays can be used for seroprevalence studies. The anti-nucleocapsid immunoassay assay is valuable in confirming past natural infection in patients with previous asymptomatic infection, previous symptomatic infection where no PCR was done or PCR-negative patients who present to hospital with COVID-19 during the second week of illness or later. Most importantly, the antispike immunoassay can be used as a reliable, cheap, and easily accessible surrogate marker of post-vaccine humoral immune response and we recommend using this to confirm and monitor humoral immune response in patients with risk factors for non-seroconversion following vaccination and increased risk for morbidity and mortality following infection with SARS-CoV-2. DA - 2022 DB - OpenUCT DP - University of Cape Town KW - laboratory sciences LK - https://open.uct.ac.za PY - 2022 T1 - Evaluation of two SARS-CoV-2 immunoassays TI - Evaluation of two SARS-CoV-2 immunoassays UR - http://hdl.handle.net/11427/37603 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/37603 | |
| dc.identifier.vancouvercitation | Naidoo M. Evaluation of two SARS-CoV-2 immunoassays. []. ,Faculty of Health Sciences ,Department of Clinical Laboratory Sciences, 2022 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/37603 | en_ZA |
| dc.language.rfc3066 | eng | |
| dc.publisher.department | Department of Clinical Laboratory Sciences | |
| dc.publisher.faculty | Faculty of Health Sciences | |
| dc.subject | laboratory sciences | |
| dc.title | Evaluation of two SARS-CoV-2 immunoassays | |
| dc.type | Master Thesis | |
| dc.type.qualificationlevel | Masters | |
| dc.type.qualificationlevel | MMed |