Diagnostics
Antigen Test
What is an antigen test?
An antigen test is a diagnostic test used to identify specific proteins, called antigens, associated with certain infections. It is a quick and efficient method for detecting the presence of pathogens in an individual’s body. Antigen tests are commonly used for diagnosing respiratory infections caused by various viruses, including influenza (flu) viruses and respiratory syncytial virus (RSV).
What are different antigen tests available?
While they gained significant attention during the COVID-19 pandemic to rapidly detect SARS-CoV-2 antigens, antigen tests, have been used for various other medical purposes even before the pandemic. Here are some common examples of antigen tests used for diseases other than COVID-19:
- Influenza Antigen Test: An influenza antigen test is used to detect the flu virus. It helps identify specific flu antigens, such as nasal swabs in respiratory samples. This test allows doctors to diagnose flu infections to provide appropriate treatment and care quickly.
- Streptococcal Antigen Test (Strep Test): The streptococcal antigen test, also known as the strep test, is used to diagnose strep throat. It looks for specific antigens produced by the group A Streptococcus bacteria in throat swab samples.
- RSV (Respiratory Syncytial Virus) Antigen Test: The RSV antigen test detects respiratory syncytial virus, which can cause respiratory infections, especially in infants and young children as well as in the elderly. This test identifies RSV antigens in respiratory samples, helping doctors diagnose the infection and manage the patient’s condition.
- HIV Antigen Test: The HIV antigen test is used to detect antigens related to the human immunodeficiency virus (HIV). It allows for quick screening for HIV infection. If the test is positive, further confirmatory tests are conducted to provide a definitive diagnosis.
- H. Pylori Antigen Test: The H. pylori antigen test is used to diagnose Helicobacter pylori infection, which can cause gastrointestinal issues like peptic ulcers. The test detects H. pylori antigens in stool or breath samples, helping doctors assess the infection and plan appropriate treatment.
- COVID-19 Antigen Test: The COVID-19 antigen test is a diagnostic test used to detect the presence of the SARS-CoV-2 virus, which causes COVID-19. It identifies specific viral proteins (antigens) in respiratory samples, typically collected through a nasal or throat swab. The test is relatively quick and can provide results within a short period, usually in less than 30 minutes.
How is the test performed?
A lab technician collects a sample from the nose and throat during an antigen test using a swab. The sample is then processed using a test kit containing antibodies to detect the target antigen. If the antigen is present in the sample, it will bind to the antibodies in the test kit, producing a visible result, often within a short period (usually minutes).
Benefits
Antigen tests offer several advantages, including:
- Rapid results: Antigen tests provide fast results, often within 30 minutes. This quick turnaround time allows for immediate decision-making and timely interventions.
- Ease of use: Antigen tests are designed to be simple to perform. They do not require a person with specialized training or expertise, making them more accessible in various healthcare settings.
- Ease of interpretation: The results of antigen tests are generally easy to interpret. They often involve visual indicators, such as lines appearing on a test strip, which can be easily understood without extensive medical knowledge.
- Affordability: Compared to other diagnostic tests, antigen tests are relatively inexpensive, making them a cost-effective option for mass testing and screening programs.
These benefits make antigen tests valuable tools in rapidly detecting and screening infectious diseases.
References
- What to know about antigen tests. Available from: https://www.medicalnewstoday.com/articles/what-is-an-antigen-test
- Considerations for SARS-CoV-2 Antigen Testing for Healthcare Providers Testing Individuals in the Community. General guidance. Available from: https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.html#anchor_1631294955610
- Centers for Disease Control and Prevention (CDC). Rapid Influenza Diagnostic tests. Available from: https://www.cdc.gov/flu/professionals/diagnosis/clinician_guidance_ridt.htm
- Cohen JF, Bertille N, Cohen R, Chalumeau M. Rapid antigen detection test for group A streptococcus in children with pharyngitis. Cochrane Database Syst Rev. 2020;8(8):CD010502
- Respiratory Syncytial Virus (RSV) Testing. Available from: https://www.testing.com/tests/respiratory-syncytial-virus-rsv-testing/
- World Health Organization (WHO). HIV and AIDS Available from: https://www.who.int/news-room/fact-sheets/detail/hiv-aids#:~:text=Most%20widely%20used%20HIV%20diagnostic,within%2028%20days%20of%20infection
- H. Pylori Breath Test (Helicobacter pylori). Available from: https://www.testing.com/tests/helicobacter-pylori-h-pylori-testing/
