What is the Difference Between Molecular and Antigen Test?

The main difference between molecular and antigen tests for COVID-19 lies in the substances they detect and their accuracy levels. Here are the key differences:

1. Substances detected: Molecular tests, such as polymerase chain reaction (PCR) and other nucleic acid amplification tests (NAATs), detect genetic material called RNA from the virus. Antigen tests, often referred to as rapid tests or at-home tests, detect proteins called antigens from the virus.
2. Accuracy: Molecular tests are generally more accurate but require trained healthcare workers, specialized equipment, and take longer to produce results. Antigen tests are faster and can be used in various settings, but they are less sensitive than molecular tests and may yield false-negative results.
3. Sample collection: Both molecular and antigen tests typically require a sample from the patient, such as a nasal swab or saliva.
4. Testing settings: Molecular tests are mostly processed in a laboratory, while antigen tests can be processed in various settings, including at-home, doctors' offices, or pharmacies.
5. Turnaround time: Molecular tests usually take longer to produce results, while antigen tests can provide results in about 15 minutes.

In summary, molecular tests are more accurate but take longer to process, while antigen tests are faster but less accurate. Antigen tests are often used for quick results or general screening, whereas molecular tests are typically relied upon when people have COVID-19 symptoms.

Comparative Table: Molecular vs Antigen Test

Here is a table comparing molecular and antigen tests for the diagnosis of COVID-19:

Molecular tests, also known as PCR tests, detect the virus's genetic material and are highly sensitive and specific. However, they take longer to produce results compared to antigen tests. Antigen tests, on the other hand, identify proteins on the virus and are generally faster than PCR tests. They have lower sensitivity compared to PCR tests and may yield false-negative results, especially when the viral load is low in the sample.