Rev Peru Med Exp Salud Publica. 2020;37(2):203-9. https://doi.org/10.17843/rpmesp.2020.372.5534 203 Citation: Vidal-Anzardo M, Solis G, Solari L, Minaya G, Ayala-Quintanilla B, Astete-Cornejo J, et al. Evaluation under field conditions of a rapid test for detection of IgM and IgG antibodies against SARS-COV-2. Rev Peru Med Exp Salud Publica. 2020;37(2):203- 9. doi: https://doi.org/10.17843/ rpmesp.2020.372.5534 _________________________________ Correspondence to: Margot Haydée Vidal Anzardo; Cápac Yupanqui 1400, Jesús María, Lima, Perú; mvidal@ins.gob.pe _________________________________ Received: 10/04/2020 Approved: 20/04/2020 Online: 22/04/2020 ORIGINAL ARTICLE EVALUATION UNDER FIELD CONDITIONS OF A RAPID TEST FOR DETECTION OF IgM AND IgG ANTIBODIES AGAINST SARS-CoV-2 Margot Vidal-Anzardo 1,a , Gilmer Solis 2,b , Lely Solari 1,c , Gabriela Minaya 2,d , Beatriz Ayala-Quintanilla 2,e , Jonh Astete-Cornejo 3,f , Amparo Luque-Aguilar 1,a,g , Ana Jorge 4,g , Nancy Rojas 5,g , Fanny Cardenas 4,g , Alonso Soto 6,7,h 1 Centro Nacional de Salud Pública, Instituto Nacional de Salud, Lima, Perú. 2 Oficina General de Investigación y Transferencia Tecnológica, Instituto Nacional de Salud, Lima, Perú. 3 Centro Nacional de Salud Ocupacional y Protección del Ambiente para la Salud, Lima, Perú. 4 Laboratorio de Referencia Nacional de Bacterias de Transmisión Sexual, Instituto Nacional de Salud, Lima, Perú. 5 Laboratorio de Referencia Nacional de Virus Respiratorio, Instituto Nacional de Salud, Lima, Perú. 6 Instituto de Investigación en Ciencias Biomédicas, Facultad de Medicina Humana. Universidad Ricardo Palma, Lima, Perú. 7 Departamento de Medicina, Hospital Nacional Hipólito Unanue, Lima, Perú. a Physician; b Dental Surgeon; c Infectologist, Doctor of Health Sciences; d Infectologist, Master of Public Health and Bioethics; e Obstetrician-gynecologist, Doctor of Medicine; f Medical Specialist in Occupational and Environmental Medicine, Master of Business Administration with specialization in Integrated Quality, Safety and Environmental Management, g Biologist, h Specialist in Internal Medicine and Doctor of Medical Sciences. ABSTRACT Objective: To determine the additional diagnostic performance of a rapid serological test for detection of IgM and IgG antibodies compared to the real-time polymerase chain reaction (RT-PCR) test; for detection of SARS-CoV-2. Materials and methods: A cross-sectional study was carried out including patients hospitalized for COVID-19 in 3 hospitals, health workers exposed to the infection and outpatients who met suspicious case criteria, all of which underwent the molecular test (RT-PCR) and the rapid serological test. e additional diagnostic performance of rapid serological test was evaluated in comparison to molecular tests. Likewise, an approximation was made to the sensitivity and specificity of the rapid serological test. Results: 144 people were included. With the rapid test, 19.4% of positive results were obtained compared to 11.1% in the molecular test (p = 0.03). e rapid serological test detected 21 cases that had been negative by the initial (RT-PCR), providing an additional diagnostic performance of 56.8% compared to the RT-PCR. e additional diagnostic performance was 50.0% during the first week, 70.0% during the second week and 50.0% during the third week of symptom onset. e sensitivity of the rapid serological test was 43.8% and the specificity of 98.9%. Conclusions: e rapid serological test was able to detect a greater number of cases than those detected by the molecular test especially aſter the second week of onset of symptoms. It also showed high specificity. It is therefore useful as a complementary test to RT-PCR, especially during the second and third week of illness. Keywords: Coronavirus; Validation Studies; Serologic Test; SARS-CoV-2; COVID-19 (source: MeSH NLM). INTRODUCTION As of April 7, 2020, the World Health Organization (WHO) reported a total of 417,416 confir- med cases and 12,597 deaths from SARS-CoV-2 virus infection (COVID-19) in the Americas, from which 2,954 confirmed cases and 107 deaths were reported from Peru (1) . e diagnosis of SARS-CoV-2 infection is made using the real-time reverse transcriptase-poly- merase chain reaction (RT-PCR) test, which detects the presence of viral RNA. is molecular test (RT-PCR) is useful in the first three weeks of infection and is currently the WHO recommended refe- rence standard (2) . However, the test has some drawbacks such as: high cost; difficulty to implement in limited-resource settings; variable sensitivity depending on the sample type (93% in bronchoalveolar lavage, 72% in sputum, 63% in nasal swabs and 32% in pharyngeal swabs) (3) ; and its low sensitivity beyond the third week of symptom onset (4)