The Rapid IgM-IgG Combined Antibody Test for COVID-19 is a lateral flow immunoassay used to qualitatively detect both early and late marker IgG/IgM antibodies in human finger-prick blood samples.

In order to test the detection sensitivity and specificity of the COVID-19 IgG-IgM combined antibody test, blood samples were collected from COVID-19 patients from multiple hospitals and Chinese CDC laboratories. The tests were done separately at each site. A total of 615 cases were tested: 403 (positive) clinically confirmed (including PCR test) COVID-19-infected patients and 212 non- COVID-19-infected patients (212 negative). The testing results of vein blood without viral inactivation were summarized in the Table 1. Of the 403 blood sample from COVID-19-infected patients, 397 tested positive, resulting in a sensitivity of 98.511%. 25 of the blood samples from the 212 non-COVID-19 infection patients tested positive, generating a specificity of 88.208%.

It is widely accepted that Immunoglobulin M (IgM) provides the first line of defence during viral infections, followed by the generation of adaptive, high affinity Immunoglobulin G (IgG) responses for long-term immunity and immunological memory. Therefore, testing of COVID-19 IgM and IgG antibodies is an effective method for the rapid diagnosis of COVID-19 infection. Detection of IgM antibodies tends to indicate a recent exposure to COVID-19. Detection of IgG antibodies indicates a later stage of infection. The testing device has a strip, which contains a colloidal gold-labelled recombinant novel coronavirus antigen and quality control antibody colloidal gold marker, two detection lines (G and M lines) and one quality control line (C) fixed on a nitrocellulose membrane. M is fixed with monoclonal anti-human IgM antibody for detecting the novel coronavirus IgM antibody. G is fixed with monoclonal antihuman IgG antibody for detecting the novel coronavirus IgG antibody.

Results are within 15 minutes after the blood sample and buffer have been combined in the testing device’s sample well.

Please make sure the kit is recovered into room temperature and perform the kit under the room temperature(15℃~30℃). The results will be affected by high or low temperature.

Serum and plasma specimens may be stored at 2-8℃ for up to 3 days. For long-term storage, specimens should be kept below -20℃. Whole blood collected by venipuncture should be stored at 2-8℃ if the test is to be run within 2 days of collection. Do not freeze whole blood specimens. Whole blood collected by fingertip should be tested immediately.