What is Covid-19
There are several diagnostic methods for COVID-19, and they can be generally classified into two categories:1
- For identifying if a person is infected with SARS-CoV-2 (current infection) from his/her respiratory specimen: RT-PCR and Antigen Test.
- For identifying if a person has developed an immune response against SARS-CoV-2 (current or previous infection) from his/her blood sample: ELISA and Antibody Test.
The healthcare workers usually interpret the results in conjunction with clinical symptoms and other clinical examinations such as Chest X-Ray, CT scan, and Ultrasound scan to make treatment and public health decisions.
Nasopharyngeal Swab. Image Credit: CDC
Each diagnostic method has its advantages and limitation. For example, RT-PCR and ELISA have high sensitivity and can provide semi-quantitative or quantitative results, however, the well-trained personnel is required. Both Antigen Test and Antibody Test are lateral flow immunoassay with simple and rapid procedures that are designed for point-of-care testing. Furthermore, RT-PCR and Antigen Test can detect SARS-CoV-2 in the early stage of infection, and serology-based tests can be used for epidemiological surveillance.1
Who Should Be Tested
- Most people will have mild illness and can recover at home without medical care and may not need to be tested.2
- If you have symptoms of COVID-19 and want to get tested, call your healthcare provider first. The decisions about testing are made by local, state, federal, or national health authorities.2
- You can also visit your state or local health department’s website to look for the latest local information on testing.2
Learn more about COVID-19 testing, please visit :
- European Commission. Current performance of COVID-19 test methods and devices and proposed performance criteria
- Centers for Disease Control and Prevention. Testing for COVID-19. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html