Use of rapid diagnostict test to select Covid-19’s convalecent plasma donors

Abstract

The use of COVID-19 Convalescent Plasma (PC-CoV19) as an adjuvant for the treatment of patients, would have a significant socioeconomic impact by reducing the length of hospital stay and lethality due to the disease. The determination of antibodies in plasma from potential donors is a fundamental criterion for their selection. There is difficulty in obtaining certified serological tests that quantify specific antibodies against SARS-CoV-2. Rapid Diagnostic Tests (PDR) become a useful and accessible tool in the selection of recovered patients, potential PC-CoV19 donors. This study evaluated the positivity rate of different PDRs in twenty-two (22) samples from patients with COVID-19 confirmed by RT-PCR. The samples were analyzed following the procedure described by each manufacturer. The performance of PDRs was analyzed in symptomatic and asymptomatic patients at different times of the disease. The positivity rate was 100% with two of the three tests used, one of which discriminates IgM from IgG. It is concluded that the presence of IgG is recorded 15 days after the onset of symptoms and remains present at day 59 of evolution in symptomatic patients, and that asymptomatic patients could be considered candidates for PC-CoV19 donors since IgG seroconversion was evident. The positivity rate to IgG could decrease in the recovered patients. It is suggested that symptomatic patients with medical discharge criteria be considered donor candidates after 28 days from the date of onset of symptoms. It is recommended to use PDRs that discriminate IgM from IgG as a tool for the selection of PC-CoV19 donors.