Types of tests available for COVID-19: who should be tested?

Who should take the test?

The Centers for Disease Control and Prevention (CDC) health guidelines for testing are as follows:

• All individuals exhibiting symptoms of COVID-19 should undergo the test after consulting their doctor.
• Individuals who were in close contact with a confirmed COVID-19 case (within 6 feet of an infected person for a total of 15 minutes or more in a 24-hour period) should undergo testing. Contact is the period considered within a period ranging from two days before the onset of the disease (or, for asymptomatic patients, two days before the test sample is taken) until the patient is isolated .
• Asymptomatic screening may be required by a health authority if you have been to an area with a high prevalence of COVID-19 patients in the past 14 days or if you are undergoing any medical procedure.

What’s the difference between the types of tests available for COVID-19?

Getting tested for COVID-19 can identify you as a positive or negative patient of the disease. Remember that no tests are 100% accurate. Several test methods have been launched to track COVID-19 infection. These are as follows:

• The test to diagnose active infection:

COVID-19 test to diagnose an active infection

Mr. No.	RT-PCR test / NAAT test	Rapid antigen test
1.	Detects the presence of the viral particle (viral ribonucleic acid [RNA]).	It detects a specific protein in the body that triggers an immune response to COVID-19 infection.
2.	Results are available from one to seven days depending on your location.	Results are fast and can be achieved in 1-24 hours.
3.	It is the best test available to confirm COVID-19 infection. The test is accurate about 60-95% of the time when done correctly.	Compared to the NAAT test, this test has a low sensitivity (approximately 56%). This means there is more risk of losing an actively infected person with this test.
4.	A nasal swab (from the nostrils) or a nasopharyngeal swab (from the back of the throat) is collected for the test.	A nasal or nasopharyngeal swab is collected for the test.

• Test to Diagnose Past COVID-19 Infection: A level of serum IgG antibodies to SARS-CoV-2 is measured to detect any previous infection.
  • The detection rate for SARS-CoV-2-IgG was 30% in the first week of infection,
  • 66% in the second week e
  • 88% in the third week.
• SARS-CoV-2 antibody test
  • It is performed through blood or a finger prick.
  • It should not be used to detect an active infection.
  • Reports can take one to three days.
  • Detect the body’s response to COVID-19 infection.

A positive antibody test does not mean that you will be immune to COVID-19 in the future.

Test kit for COVID-19:

The following test kits are available on the market for sample collection. Most test kits use the RT-PCR method to diagnose the virus.

• Rapid point-of-care diagnostic tests use a mucus sample from the nose or throat. This test is performed at the doctor’s clinic where the sample is collected and the results are available within minutes. These tests can be molecular or antigen-based.
• Combined tests are used for the detection of influenza and coronavirus at the same time. Some can test for many different types of respiratory viruses, including SARS-CoV-2.
• Saliva tests allow a patient to spit into a test tube rather than using nasal or throat swabs. Some people may prefer the saliva test to swabs. These are also safer for healthcare professionals when collecting samples.
• Home collection tests, available only on doctor’s prescription, allow the patient to take the sample from the back of the throat and send it directly to the laboratory