Comparative analysis of three point-of-care lateral flow immunoassays for detection of anti-SARS-CoV-2 antibodies: data from 100 healthcare workers in Brazil

Abstract

Since the coronavirus disease 2019 (COVID-19) pandemic, Brazil has the third-highest number of confirmed cases and the second-highest number of recovered patients. SARS-CoV-2 detection by real-time RT-PCR is the gold standard but requires a certified laboratory infrastructure with high-cost equipment and trained personnel. However, for large-scale testing, diagnostics should be fast, cost-effective, widely available, and deployed for the community, such as serological tests based on lateral flow immunoassay (LFIA) for IgM/IgG detection. We evaluated three different commercial point-of-care (POC) LFIAs for anti-SARS-CoV-2 IgM and IgG detection in capillary whole blood of 100 healthcare workers (HCW) from São Paulo university hospital previously tested by RT-PCR: (1) COVID-19 IgG/IgM BIO (Bioclin, Brazil), (2) Diagnostic Kit for IgM/IgG Antibody to Coronavirus (SARS-CoV-2) (Livzon, China), and (3) SARS-CoV-2 Antibody Test (Wondfo, China). A total of 84 positives and 16 negatives HCW were tested. The data was also analyzed by the number of days post symptoms (DPS) in three groups: <30 ( n =26), 30–59 ( n =42), and >59 ( n =16). The observed sensibility was 85.71%, 47.62%, and 44.05% for Bioclin, Wondfo, and Livzon, respectively, with a specificity of 100% for all LFIA. Bioclin was more sensitive ( p <0.01), regardless of the DPS. Thus, the Bioclin may be used as a POC test to monitor SARS-CoV-2 seroconversion in HCW.

Testing Denmark: a Danish Nationwide Surveillance Study of COVID-19

“…The low seroprevalence at 0.79% in our study may be due to low sensitivity of the POCT used or due to difficulties in reading the test results, since 2.9% were inconclusive. POCT in general have a lower diagnostic performance compared to laboratory testing ( 14 ) and the Livzon POCT have been found to have a lower-than-expected sensitivity ( 15 , 16 ). Test results also depend on the prevalence of infection in the population which will be low when screening asymptomatic and higher for those with suggestive symptoms.…”

A systematic review and meta-analysis comparing the diagnostic accuracy tests of COVID-19

“…Six studies were selected using LFIA as an IgM detection technique [75,77,79,111,112,115], in which a total of 2,704 subjects were studied. Sensitivity ranged from 23.3% to 87.2%, with a median of 62.4%, 95%CI (51.1, 72.5), while the test for equality of sensitivities presented a χ 2 = 208.82, df = 11, p-value = 2e -16 .…”

Evaluation of eleven immunochromatographic assays for SARS-CoV-2 detection: investigating the dengue cross-reaction

“…The TBG assay reached a sensitivity and specificity of 99.8%, using samples after the 15 th day of symptoms 24 . The Wondfo and Bioclin assays were evaluated by Conte and colleagues in finger prick samples derived from Brazilian healthcare workers, the sensitivity was 47.62% and 85.7%, respectively 25 . Another Brazilian study that evaluated different IC assays reported a sensitivity of 81.71% and 84.15%, and specificity of 78.38% and 100% for Ecotest and Medtest, respectively 26 .…”