Background Low- and middle-income countries (LMICs) are increasingly adopting low-cost Coronavirus disease 2019 (COVID-19) rapid antigen tests to meet the high demand for SARS-CoV-2 testing. Whilst testing using real-time polymerase chain reaction (RT-PCR) is the current gold standard, its widespread use in LMICs is limited by high costs, turnaround times and is not readily available in most places. COVID-19 antigen tests (Ag-RDT) provide a suitable alternative due to their low cost, rapid turnaround time and easy to set up and use. This study aimed to assess the field performance of the NowCheck COVID-19 antigen kit (Ag-RDT) as a point of care test (POCT) in select healthcare facilities in western Kenya. Methods We conducted a prospective multi-facility field evaluation study of the NowCheck COVID-19 rapid antigen test (Ag-RDT) compared to SARS-CoV-2 RT-PCR (RT-PCR). After obtaining informed consent, trained laboratory technicians collected two pairs of oropharyngeal and nasopharyngeal swabs, both antigen and RT-PCR testing, first for Ag-RDT and next for RT-PCR. We performed Ag-RDTs on-site and shared the results with both the study participants and their healthcare providers within 15-30 minutes. We carried out all RT-PCR tests in a central referral laboratory. The turnaround time for RT-PCR results was typically 24-48 hours. We captured the results of both methods using an electronic digital application. Findings Between December 2020 and March 2021, we enrolled 997 participants who met the Kenyan Ministry of Health COVID-19 case definition. The median age of study participants was 39 years (range one to 80 years), with 54% male. Ag-RDT had a sensitivity of 84.5% (76.0-90.8) and a specificity of 94.4% (95% CI: 92.7-95.8) with an accuracy of 94.2% (92.5- 95.6) when a cycle threshold value (Ct value) of ≤35 was used. The highest sensitivity of 87.7% (77.2-94.5) was observed in samples with Ct values ≤ 30 and the highest specificity of 97.5% (96.2-98.5) at Ct value of <40. Interpretation The NowCheck COVID-19 Ag-RDT showed good performance in field evaluation in multiple healthcare facilities in a developing country. The sensitivity of the kit exceeded the minimum recommended cut-off of 80% as recommended by WHO1. The high specificity of this kit at 94.4% at Ct values ≤33 and 97.5% at Ct values <40 matched that of real-time PCR, making it a good rule-out test for symptomatic patients with COVID-19- like symptoms. The faster turnaround time to results, lower cost, simple analytical steps requiring no equipment or infrastructure makes antigen testing an attractive field-screening method to meet the high demand for COVID-19 testing.

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COVID-19 pandemic remains a major global public health challenge also in Low- and Middle-Income Countries (LMIC), due to fragile health systems, limited resources and personnel, low testing and counseling capacity, community perceptions, among others. In Kisumu County of Western Kenya, a unique Public Private Partnership (PPP) was rolled-out to increase testing and capacity building by linking private facilities to the ongoing public sector efforts in combating COVID-19. It became increasingly clear that centralized PCR testing for COVID-19 was too labor-intensive, expensive, prone to machine breakdowns and stock-outs of essential reagents, resulting in long turn-around times and sometimes even adaptations of patient selection criteria. A clear need was identified for rapid point-of-care COVID-19 testing (AgRDT). After successful field evaluation, RDT for COVID-19 was offered through the PPP. This paper aimed to understand the health workers perspective on the feasibility and acceptability of the introduction of the AgRDT in Kisumu County.In-Depth Interviews were conducted with selected health workers (n=23) from the participating facilities and analyzed using Nvivo 11 The health workers accepted the use of AgRDT as it enabled the strengthening of the existing health system, increased testing capacity and provided capacity building opportunities. Challenges included poor management of results discrepant with PCR gold standard.The health workers applauded the introduction of AgRDT with the Kisumu County Department of Health as a more realistic and user-friendly approach, leading to fast turn-around times and increased personal safety experience.

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