Most self-COVID tests authorized for use in India and abroad are a form of antigen testing, which tell you about your COVID status (whether positive or negative) in a short time.
Antigen and molecular tests used for COVID testing work to identify the presence of viral components in the body. Antigen tests, particularly, which form the backing of several quick-result delivering at-home COVID tests use a technology to trace the protein in the virus strain in the body and dole out a positive or negative test. Compared to this, molecular testing, also known as PCR (Polymerase Chain Reaction ) testing helps identify the RNA, or the genetic component of the virus, and is hence ranked to be gold-standard tests.
Both the tests, however, are administered in the same manner- using a throat/nasal swab that sample the saliva to trace the virus. The reason why PCR and antigen tests have such a varied difference in respect to the result delivery times is that while PCR technology requires specialized, often expensive diagnostic equipment and runs the virus component through repeat cycles to find the result, antigen tests look for the protein, and the results can be easily verified at an economical, time-effective manner. So to say, while self-COVID tests can deliver results in 15-20 minutes, PCR tests can take upto a minimum of 24 hours to deliver results, or more if there’s a high demand for the testing.