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Samsunder N, Sivro A, Hassan-Moosa R, Lewis L, Kara Z, Baxter C, Karim QA, Karim SA, Kharsany ABM, Naidoo K, Ngcapu S. Evaluating diagnostic accuracy of an RT-PCR test for the detection of SARS-CoV-2 in saliva. Diagn Progn Res 2024; 8:9. [PMID: 39044271 PMCID: PMC11267770 DOI: 10.1186/s41512-024-00176-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 07/01/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND AND OBJECTIVE Saliva has been proposed as a potential more convenient, cost-effective, and easier sample for diagnosing SARS-CoV-2 infections, but there is limited knowledge of the impact of saliva volumes and stages of infection on its sensitivity and specificity. METHODS In this study, we assessed the performance of SARS-CoV-2 testing in 171 saliva samples from 52 mostly mildly symptomatic patients (aged 18 to 70 years) with a positive reference standard result at screening. The samples were collected at different volumes (50, 100, 300, and 500 µl of saliva) and at different stages of the disease (at enrollment, day 7, 14, and 28 post SARS-CoV-2 diagnosis). Imperfect nasopharyngeal (NP) swab nucleic acid amplification testing was used as a reference. We used a logistic regression with generalized estimating equations to estimate sensitivity, specificity, PPV, and NPV, accounting for the correlation between repeated observations. RESULTS The sensitivity and specificity values were consistent across saliva volumes. The sensitivity of saliva samples ranged from 70.2% (95% CI, 49.3-85.0%) for 100 μl to 81.0% (95% CI, 51.9-94.4%) for 300 μl of saliva collected. The specificity values ranged between 75.8% (95% CI, 55.0-88.9%) for 50 μl and 78.8% (95% CI, 63.2-88.9%) for 100 μl saliva compared to NP swab samples. The overall percentage of positive results in NP swabs and saliva specimens remained comparable throughout the study visits. We observed no significant difference in cycle number values between saliva and NP swab specimens, irrespective of saliva volume tested. CONCLUSIONS The saliva collection offers a promising approach for population-based testing.
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Affiliation(s)
- Natasha Samsunder
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
| | - Aida Sivro
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban, South Africa
- JC Wilt Infectious Disease Research Centre, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada
| | - Razia Hassan-Moosa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
- SAMRC-CAPRISA HIV-TB Pathogenesis and Treatment Research Unit, Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, South Africa
| | - Lara Lewis
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
| | - Zahra Kara
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
| | - Cheryl Baxter
- Centre for Epidemic Response and Innovation (CERI), Stellenbosch University, Stellenbosch, South Africa
| | - Quarraisha Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
- Department of Epidemiology, Columbia University, New York, NY, USA
| | - Salim Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
- Department of Epidemiology, Columbia University, New York, NY, USA
| | - Ayesha B M Kharsany
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban, South Africa
| | - Kogieleum Naidoo
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa
- SAMRC-CAPRISA HIV-TB Pathogenesis and Treatment Research Unit, Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, South Africa
| | - Sinaye Ngcapu
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), 719 Umbilo Road, Durban, 4001, South Africa.
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban, South Africa.
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Bravo-González S, González-González E, Perales-Salinas V, Rodríguez-Sánchez IP, Ortiz-Castillo JE, Vargas-Martínez A, Perez-Gonzalez VH, Luna-Aguirre CM, Trujillo-de Santiago G, Alvarez MM. Self-Diagnosis of SARS-CoV-2 from Saliva Samples at Home: Isothermal Amplification Enabled by Do-It-Yourself Portable Incubators and Laminated Poly-ethyl Sulfonate Membranes. Diagnostics (Basel) 2024; 14:221. [PMID: 38275468 PMCID: PMC10814948 DOI: 10.3390/diagnostics14020221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/04/2023] [Accepted: 12/07/2023] [Indexed: 01/27/2024] Open
Abstract
COVID-19 made explicit the need for rethinking the way in which we conduct testing for epidemic emergencies. During the COVID-19 pandemic, the dependence on centralized lab facilities and resource-intensive methodologies (e.g., RT-qPCR methods) greatly limited the deployment of widespread testing efforts in many developed and underdeveloped countries. Here, we illustrate the development of a simple and portable diagnostic kit that enables self-diagnosis of COVID-19 at home from saliva samples. We describe the development of a do-it-yourself (DIY) incubator for Eppendorf tubes that can be used to conduct SARS-CoV-2 detection with competitive sensitivity and selectivity from saliva at home. In a proof-of-concept experiment, we assembled Eppendorf-tube incubators at our home shop, prepared a single-tube mix of reagents and LAMP primers in our lab, and deployed these COVID-19 detection kits using urban delivery systems (i.e., Rappifavor or Uber) to more than 15 different locations in Monterrey, México. This straightforward strategy enabled rapid and cost-effective at-home molecular diagnostics of SARS-CoV-2 from real saliva samples with a high sensitivity (100%) and high selectivity (87%).
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Affiliation(s)
- Sergio Bravo-González
- Centro de Biotecnología-FEMSA, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (S.B.-G.); (E.G.-G.); (V.P.-S.); (C.M.L.-A.)
- Departamento de Bioingeniería, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico
| | - Everardo González-González
- Centro de Biotecnología-FEMSA, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (S.B.-G.); (E.G.-G.); (V.P.-S.); (C.M.L.-A.)
- Departamento de Bioingeniería, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico
| | - Valeria Perales-Salinas
- Centro de Biotecnología-FEMSA, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (S.B.-G.); (E.G.-G.); (V.P.-S.); (C.M.L.-A.)
- Departamento de Bioingeniería, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico
| | - Iram Pablo Rodríguez-Sánchez
- Laboratorio de Fisiología Molecular y Estructural, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza 66455, NL, Mexico;
- Alfa Medical Center, Guadalupe 67100, NL, Mexico
| | - Jose E. Ortiz-Castillo
- Departamento de Ingeniería Mecátrónica y Eléctrica, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (J.E.O.-C.); (A.V.-M.); (V.H.P.-G.)
| | - Adriana Vargas-Martínez
- Departamento de Ingeniería Mecátrónica y Eléctrica, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (J.E.O.-C.); (A.V.-M.); (V.H.P.-G.)
| | - Victor H. Perez-Gonzalez
- Departamento de Ingeniería Mecátrónica y Eléctrica, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (J.E.O.-C.); (A.V.-M.); (V.H.P.-G.)
| | - Claudia Maribel Luna-Aguirre
- Centro de Biotecnología-FEMSA, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (S.B.-G.); (E.G.-G.); (V.P.-S.); (C.M.L.-A.)
- Departamento de Bioingeniería, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico
| | - Grissel Trujillo-de Santiago
- Centro de Biotecnología-FEMSA, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (S.B.-G.); (E.G.-G.); (V.P.-S.); (C.M.L.-A.)
- Departamento de Ingeniería Mecátrónica y Eléctrica, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (J.E.O.-C.); (A.V.-M.); (V.H.P.-G.)
| | - Mario Moisés Alvarez
- Centro de Biotecnología-FEMSA, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (S.B.-G.); (E.G.-G.); (V.P.-S.); (C.M.L.-A.)
- Departamento de Ingeniería Mecátrónica y Eléctrica, Tecnologico de Monterrey, Monterrey 64849, NL, Mexico; (J.E.O.-C.); (A.V.-M.); (V.H.P.-G.)
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