How does Covid-19 Antigen, Antibody and Nucleic acid detection work?

Panodyne Covid-19 Detection Science Image Multibrands

The COVID-19 is an RNA virus with acute respiratory tract infection. It is spherical in shape, with crowned spikes on the surface, ribonucleic acid strand (RNA) inside, and a shell composed of multiple proteins on the outside.

At present, three technologies are mainly used to diagnose whether they are infected by the COVID-19, Nucleic Acid Detection, Antibody Detection and Antigen Detection technology.

Did you know? Nucleic acid detection uses the unique gene sequence of the virus as the detection target. Through PCR amplification, the target DNA sequence we choose increases exponentially. Each amplified DNA sequence can be combined with a previously added fluorescent sequence. The light-labeled probe binds to produce a fluorescent signal. The more target genes amplified, the stronger the accumulated fluorescent signal. In samples without virus, since there is no target gene amplification, no increase in fluorescence signal can be detected. It requires professional operation and is time-consuming.

The target of Antibody detection is not against the virus itself, but the specific antibody produced by the immune response after the human body is infected with the virus. It is used for the auxiliary diagnosis of the COVID-19. It is complementary to other detection methods and reduces the missed detection of patients. In the early stage of the disease, it may be impossible to detect due to less antibody production. The sample is safe, low cost, stable reagents can be stored and transported at room temperature, and the detection is fast. As with Panodyne Covid-19 Antibody test kit, no testing equipment is required and it is suitable for medical institutions at all levels. The result is interpreted by CT line.

Antigen detection is aimed at the detection of pathogens themselves. Based on the basic principle of antigen-antibody reaction, atopic antibodies against specific epitopes are prepared and combined with viral structural proteins in vitro to form immune complexes, thereby detecting the new coronavirus in the specimen. This is the case with Lateral flow devices, such as the Panodyne antigen test kit for example. The biggest disadvantage is the low detection sensitivity, so it is only suitable for the acute infection period with high viral load.

Neutralizing antibody: SARS-CoV-2 uses the surface spike protein (S protein) to attach and invade host cells. The neutralizing antibody can recognize the virus surface protein, block the virus from binding to specific receptors on the cell surface, and prevent the virus from continuing to invade human cells. Neutralizing antibodies are antibodies that block virus invasion. Antibodies such as IgG/IgM are antibodies produced by the body after virus invasion. For instance, our Panodyne Covid-19 Neutralising Antibody test kits help evaluate vaccine efficacy, monitor infection rate, herd immunity and protective immunity, and evaluate vaccine efficacy during clinical trials and after mass vaccination.


Antigen, Nucleic acid, and Antibody detection are detection methods applied at different times after virus infection. Neutralizing antibody is an evaluation and monitoring method to evaluate the effectiveness of vaccines and whether recovered patients are immune to the virus, etc.

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