Feasibility of home-based ELISA capillary blood self-testing for anti-SARS-CoV-2 antibodies

Stéphanie Baggio; Giuseppe Togni; Isabella Eckerle; Nicolas Vuillemier; Laurent Kaiser; Laurent Gétaz

doi:10.1016/j.plabm.2022.e00290

Feasibility of home-based ELISA capillary blood self-testing for anti-SARS-CoV-2 antibodies

Pract Lab Med. 2022 Aug:31:e00290. doi: 10.1016/j.plabm.2022.e00290. Epub 2022 Jul 12.

Authors

Stéphanie Baggio^{1

2}, Giuseppe Togni³, Isabella Eckerle^{4

5

6

7}, Nicolas Vuillemier^{8

9}, Laurent Kaiser^{5

6

10}, Laurent Gétaz^{1

11}

Affiliations

¹ Division of Prison Health, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
² Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland.
³ Microbiology Lab, Unilabs, Coppet, Switzerland.
⁴ Department of Molecular Medicine and Microbiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
⁵ Center for Emerging Viral Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
⁶ Division of Infectious Diseases, Department of Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
⁷ Laboratory of Virology, Division of Laboratory Medicine, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
⁸ Division of Laboratory Medicine, Department of Diagnostics, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
⁹ Division of Laboratory Medicine, Department of Medical Specialties, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
¹⁰ Department of Medicine, Faculty of Medicine, University of Geneva, Switzerland.
¹¹ Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland.

Abstract

Objectives: Serological assays for the presence of anti-SARS-CoV-2 antibodies are crucially needed for research and monitoring of the SARS-CoV-2 pandemic. Antibodies are reliability detected in capillary blood, a minimally invasive and cost-effective alternative to venous blood testing. However, there is a limited knowledge on feasibility of capillary blood self-sampling. This study compared the feasibility of capillary blood self-testing in people aged less than 65 vs. people aged 65 or more. A secondary aim was to investigate the performance of the Hem-Col® (no additive) device compared to venous blood testing.

Design and methods: Data were collected in a prospective study in Switzerland (n = 106). Capillary blood was collected using the Hem-Col® (no additive) device. Feasibility was assessed using 1) collecting the recommended amount of capillary blood and 2) achieving all steps of capillary blood collection. A sample of 5 ml of venous blood was also collected.

Results: For the primary objective, 86.2%/62.1% of patients aged less than 65 collected the recommended amount of capillary blood/achieved all steps vs. 62.5%/39.6% of patients aged 65 or more (p = .006/p = .022). For the secondary objective, the correlation between capillary and venous blood was r = 0.992 and kappa = 1.

Conclusions: Capillary blood self-testing appeared as a feasible and reliable alternative to venous blood testing. Such alternative would improve access to serological testing and spare health care resources. However, the difference between age groups should be considered when using self-sampling devices. Help should be developed for older people, such as phone counseling or encouraging asking younger family members for help.

Keywords: Antibodies; COVID-19; Covid-19, Coronavirus disease of 2019; ELISA, Enzyme-linked immunosorbent assays; IgG, Immunoglobulin G; OR, Odd-ratio; RT-PCR, Real-time reverse transcription–polymerase chain reaction; SARS-CoV-2; SARS-CoV-2, Severe acute respiratory syndrome coronavirus 2; Serological testing.