Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics
Background: The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has seen a surge in the development of diagnostic assays. However, the performance of antigen point-of-care tests (Ag-POCTs) on samples with low viral load has not been evaluated. Aim: To evaluate the accuracy...
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AOSIS
2025-03-01
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| Series: | African Journal of Primary Health Care & Family Medicine |
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| Online Access: | https://phcfm.org/index.php/phcfm/article/view/4671 |
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| author | Ivy Rukasha |
| author_facet | Ivy Rukasha |
| author_sort | Ivy Rukasha |
| collection | DOAJ |
| description | Background: The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has seen a surge in the development of diagnostic assays. However, the performance of antigen point-of-care tests (Ag-POCTs) on samples with low viral load has not been evaluated.
Aim: To evaluate the accuracy of three World Health Organization (WHO) certified Ag-POCTs in comparison to the reverse transcription polymerase chain reaction (RT-PCR) technique.
Setting: The study was conducted at Pietersburg Hospital Limpopo, South Africa between March 2020 and April 2023.
Methods: A total of 371 SARS-CoV-2 nasopharyngeal samples from the National Health Laboratory Service were tested using Ag-POCTs from Abbott Panbio, Roche RDT and SD Biosensor, following manufacturer instructions. All samples had RT-PCR results with Ct values between 13 and 45. Reverse transcription polymerase chain reaction results were compared and correlated with Ag-POCT results.
Results: Of the 371 samples, the SD Biosensor Standard Q test kit detected the most positive isolates 166 (44.7%), followed by the Abbott Panbio. A total of 153 (41.2%) positives, while the Roche SD detected 134 (36.1%) samples. High viral load (Ct 25) sensitivity and specificity exceeded 77%, while intermediate (Ct 25–35) and low viral load (Ct 35) sensitivity and sensitivity dropped to 32% and 7%, respectively.
Conclusion: The performance rapid antigen tests was low on samples with low viral load with results markedly different from the manufacturer’s reported performance.
Contribution: Rapid antigen tests should not be used alone for diagnosis, especially in samples with low viral load. |
| format | Article |
| id | doaj-art-71cecd8da60d44ce97b9a14d5e65792e |
| institution | OA Journals |
| issn | 2071-2928 2071-2936 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | AOSIS |
| record_format | Article |
| series | African Journal of Primary Health Care & Family Medicine |
| spelling | doaj-art-71cecd8da60d44ce97b9a14d5e65792e2025-08-20T01:50:57ZengAOSISAfrican Journal of Primary Health Care & Family Medicine2071-29282071-29362025-03-01171e1e710.4102/phcfm.v17i1.46711229Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemicsIvy Rukasha0Department of Pathology, Faculty of Health Sciences, University of Limpopo, Polokwane, South Africa; and Department of Medical Microbiology, National Health Laboratory Services, PolokwaneBackground: The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has seen a surge in the development of diagnostic assays. However, the performance of antigen point-of-care tests (Ag-POCTs) on samples with low viral load has not been evaluated. Aim: To evaluate the accuracy of three World Health Organization (WHO) certified Ag-POCTs in comparison to the reverse transcription polymerase chain reaction (RT-PCR) technique. Setting: The study was conducted at Pietersburg Hospital Limpopo, South Africa between March 2020 and April 2023. Methods: A total of 371 SARS-CoV-2 nasopharyngeal samples from the National Health Laboratory Service were tested using Ag-POCTs from Abbott Panbio, Roche RDT and SD Biosensor, following manufacturer instructions. All samples had RT-PCR results with Ct values between 13 and 45. Reverse transcription polymerase chain reaction results were compared and correlated with Ag-POCT results. Results: Of the 371 samples, the SD Biosensor Standard Q test kit detected the most positive isolates 166 (44.7%), followed by the Abbott Panbio. A total of 153 (41.2%) positives, while the Roche SD detected 134 (36.1%) samples. High viral load (Ct 25) sensitivity and specificity exceeded 77%, while intermediate (Ct 25–35) and low viral load (Ct 35) sensitivity and sensitivity dropped to 32% and 7%, respectively. Conclusion: The performance rapid antigen tests was low on samples with low viral load with results markedly different from the manufacturer’s reported performance. Contribution: Rapid antigen tests should not be used alone for diagnosis, especially in samples with low viral load.https://phcfm.org/index.php/phcfm/article/view/4671poor performancepoint-of-care testscovid-19low viral loadantigen testsdiagnostic accuracysars cov-2. |
| spellingShingle | Ivy Rukasha Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics African Journal of Primary Health Care & Family Medicine poor performance point-of-care tests covid-19 low viral load antigen tests diagnostic accuracy sars cov-2. |
| title | Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics |
| title_full | Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics |
| title_fullStr | Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics |
| title_full_unstemmed | Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics |
| title_short | Limitations of point-of-care testing for low SARS CoV-2 loads: Insights for future pandemics |
| title_sort | limitations of point of care testing for low sars cov 2 loads insights for future pandemics |
| topic | poor performance point-of-care tests covid-19 low viral load antigen tests diagnostic accuracy sars cov-2. |
| url | https://phcfm.org/index.php/phcfm/article/view/4671 |
| work_keys_str_mv | AT ivyrukasha limitationsofpointofcaretestingforlowsarscov2loadsinsightsforfuturepandemics |