SARS-CoV-2 (Covid-19) is an infectious disease caused by the most recently discovered coronavirus. COVID-19 IgG/IgM Rapid Test (Whole Blood/ Serum/Plasma) is a rapid chromatographic immunoassay for the qualitative of IgG and IgM antibodies to COVID-19 in human whole blood, serum or plasma.
Easier: No special equipment needed, Intuitive visual interpretation.
Rapid: Quick sampling by fingertip blood, Results in 10-15min.
Accurate: Results with IgG and IgM respectively.
Application: as screening tool for potential suspect patients in large numbers.
How Should We Interpret IgM/IgG Serological Test Results?
The present IgM/IgG serological assays are designed to complement RT-qPCR in the diagnosis of SARS-CoV-2 infections. The Table below shows the clinical interpretation when testing a patient with both RT-qPCR and an IgM/IgG serological test.
Table: Clinical Significance of an IgM/IgG Serological Test Result
This table is based on the recent research and clinical data available on the regulation of SARS-CoV-2 RNA and antigens, IgM antibody and IgG antibody (Figure 1) and the correlation of these level variations with the initial time of infection, onset of symptoms and recovery phase. As shown in graph below, serological tests are recommended to be used on patients at least 3 days after onset of symptoms or 7-10 days after infection with the virus.
Figure 1: Variation of the Levels of SARS-CoV-2 RNA and Antigen, IgM and IgG after infection.
It is understood that the results of RT-qPCR and IgM/IgG serological tests do not necessarily need to agree. A disagreement between the two tests, if any, can often be traced to the after-infection time points at which the tests were performed. Overall, while RT-qPCR testing may be appropriate for the detection of the SARS-CoV-2 virus during the acute phase, IgM/IgG is an appropriate test during the chronic phase. Since the exact time of infection is often unknown, combining RT-qPCR and IgM/IgG testing can improve the accuracy of the COVID-19 diagnosis.
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2. Lauer, S. et al., 2020. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Annals of Internal Medicine.
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4. To KK, Tsang OT, Leung WS, Tam AR, Wu TC, Lung DC et al. (2020). Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect Dis. 2020 Mar 23. pii: S1473-3099(20)30196-1.
Dr Jayaraman D. Lead Scientist, leading CRO company
I have been working with a team from KRISHGEN on an assay development and customization before giving us. The project was complicated and needed technical expertise in immunology. I was very pleased with their technical competence and also mastering immunology and delivering a tough project to us on time. Their rigor, punctuality and expertise have been a recipe for the high standards, I would expect for such project from them. Kudos, Krishgen Team!!!
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