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

COVID-19 disease is spread worldwide and diagnostic techniques have been studied in order to contain the pandemic. Immunochromatographic (IC) assays are feasible and a low-cost alternative especially in low and middle-income countries, which lack structure to perform certain diagnostic techniques. Here we evaluate the sensitivity and specificity of eleven different IC tests in 145 serum samples from confirmed cases of COVID-19 using RT-PCR and 100 negative serum samples from blood donors collected in February 2019. We also evaluated the cross-reactivity with dengue using 20 serum samples from patients with confirmed diagnosis for dengue collected in early 2019 through four different tests. We found high sensitivity (92%), specificity (100%) and an almost perfect agreement (Kappa 0.92) of IC assay, especially when we evaluated IgG and IgM combined after 10 days from the onset of symptoms with RT-PCR. However, we detected cross-reactivity between dengue and COVID-19 mainly with IgM antibodies (5 to 20% of cross-reaction) and demonstrated the need for better studies about diagnostic techniques for these diseases.

SARS-CoV-2 and the COVID-19 disease: a mini review on diagnostic methods.

Coronavirus disease 2019 (COVID-19) is an infectious disease initially reported in China and currently worldwide dispersed caused by a new coronavirus (SARS-CoV-2 or 2019-nCoV) affecting more than seven million people around the world causing more than 400 thousand deaths (on June 8th, 2020). The diagnosis of COVID-19 is based on the clinical and epidemiological history of the patient. However, the gold standard for COVID-19 diagnosis is the viral detection through the amplification of nucleic acids. Although the quantitative Reverse-Transcription Polymerase Chain Reaction (RT-PCR) has been described as the gold standard for diagnosing COVID-19, there are several difficulties involving its use. Here we comment on RT-PCR and describe alternative tests developed for the diagnosis of COVID-19.