Today I will discuss the three different types of testing available for the detection of COVID-19. I will briefly discuss diagnostic and antibody (non-diagnostic) tests.
Of the diagnostic tests available, the MOLECULAR or RT-PCR test is the most accurate and considered the gold standard. The RT-PCR detects genetic material (RNA or RNA fragments) inside the coronavirus. The ANTIGEN test detects antigens that are on the surface of the virus. It is a fairly accurate test but not as accurate as the RT-PCR. The ANTIBODY test detects antibodies that you have made in response to the coronavirus. It takes several days after infection for your body to produce antibodies.
MOLECULAR TEST RT-PCR
Nasal or throat swab
Very accurate
May remain positive 3 months after infection
Detect active disease
Results in 1-7 + days
Limitations to mass production
Highly sensitive
Expensive ($35-$200)
ANTIGEN TEST
Nasal or throat swab
Less accurate than molecular, but still accurate
Detect active disease
Results in < 1 hour
If results negative, but symptomatic, may need to retest with an RT-PCR
Expensive ($35-$200)
ANTIBODY TEST
Blood test via finger stick
Not diagnostic
Detect past infection
Takes days to weeks to develop antibodies so testing should be performed a minimum of 4 days + after exposure
Results in minutes to days
Expensive ($35-$200)
The RT-PCR and Antigen tests are useful for diagnostic purposes in children or adults who have either been exposed to a known case of COVID-19 or in those who have symptoms consistent with COVID-19 like fever and cough. The antibody test is a good test for those who just want to know if they have been infected in the past.
If you feel you need to be tested, it is best to contact your doctor. Your doctor will be able to either perform the test or refer you to a different location to be tested.