What is the Difference Between Antigen and Antibody Test?
🆚 Go to Comparative Table 🆚The main difference between antigen and antibody tests lies in what they detect and when they are used. Here are the key differences:
- Antigen Test: This test looks for the presence of an active infection by detecting specific proteins (antigens) on the surface of the virus or bacteria. Antigen tests are used to diagnose current infections, such as SARS-CoV-2, the virus that causes COVID-19.
- Antibody Test: This test looks for signs of a past infection by detecting the presence of specific antibodies in a person's blood or serum. Antibodies are Y-shaped proteins produced by the immune system when it detects antigens. Antibody tests are typically not used to diagnose current infections, as the body takes time to produce antibodies after exposure to an infection.
In summary:
- Antigen tests detect active infections.
- Antibody tests detect past infections.
These tests are often used in combination to diagnose and monitor infections. For example, in the case of COVID-19, a positive antigen test result indicates an active infection, while a positive antibody test result indicates a past infection.
Comparative Table: Antigen vs Antibody Test
Here is a table summarizing the differences between antigens and antibodies:
| Feature | Antigen | Antibody |
|---|---|---|
| Definition | Antigens are substances that prompt the body to trigger an immune response against them, such as allergens, bacteria, and viruses. | Antibodies, also known as immunoglobulins, are Y-shaped proteins produced by B cells of the immune system in response to antigens. |
| Function | Antigens cause disease and trigger an immune response in the body. | Antibodies bind and neutralize antigens, either by direct neutralization or by tagging them for other arms of the immune system. |
| Testing | Antigen tests look for active infections, typically with lower sensitivity than PCR tests but providing faster results and being more amenable to point-of-care use. | Antibody tests look for signs of past infections, indicating that the body has been exposed to the antigen and produced antibodies against it. |
| Role in Vaccinations | Vaccines contain antigens that stimulate the B cells to produce antibodies, which can recognize future exposure to the disease. | Vaccines teach antibodies the correct format in which to capture or tag the antigen, allowing the immune system to rapidly respond with minimal discomfort and inconvenience. |
In summary, antigens are substances that prompt an immune response, while antibodies are proteins produced by the immune system to neutralize antigens. Antigen tests are used to detect active infections, whereas antibody tests indicate past exposure to antigens. Both antigens and antibodies play crucial roles in the development of vaccines.
- Antigen vs Antibody
- Molecular vs Antigen Test
- Antigen vs NAAT Test
- Antiserum vs Antibody
- Immunoglobulin vs Antibody
- Allergen vs Antigen
- Antigen vs Immunogen
- Antibodies vs T Cells
- Hapten vs Antigen
- Antigen vs Pathogen
- A vs B Antigens
- O vs H Antigen
- Alloantibody vs Autoantibody
- Serum vs Antiserum
- ELISA vs Rapid Test
- Complete vs Incomplete Antibodies
- Monoclonal Antibodies vs Polyclonal Antibodies
- Serology vs Immunology
- Self vs Non Self Antigens