What types of test are available?
There are two categories of tests available.
Diagnostic Testing: Polymerase Chain Reaction (PCR). Presence or Absence of the virus.
This is a done by looking for viral RNA. Obtained with a nasal or throat swab. One test company also provides fecal sample testing.
A positive test confirms that you have the Covid-19 virus.
A negative test indicates that you do not have the virus OR that you are in the initial stages of viral infection. During initial stages of infection, viral counts are low and may cause a false negative result. If you have symptoms and test negative, a repeat test 1-2 weeks later is important to confirm test results.
Sample collection. Samples can be obtained via oral or nasal samples. Most tests are limited to hospitals and public health institutions.
Fecal PCR testing. There is evidence that the Covid-19 virus may continue to shed via the fecal route up to 5 weeks after clearance in the respiratory system. This test is available with physician ordering only.
A fecal PCR test is not officially diagnostic for Covid-19, but may help determine:
- If a Covid-19 patient continues to be a risk to others.
- Help determine transmission risk from an asymptomatic person with possible viral exposure.
- Possible infection in someone with Covid-19 symptoms.
For locations for Diagnostic Testing, See Article Can you get tested for Covid-19?
Immune reaction testing: Immunoglobulin IgM/IgG.
Currently only FDA approved tests are available and are limited. Testing availability should increase in the near future.
This blood test evaluates an immune response to the virus. Immunoglobulins are important immune proteins that react to infection.
It is NOT diagnostic for viral infection. It is NOT diagnostic for immunity.
This test evaluates for an early or ongoing immune response to viral exposure.
- IgM. IgM immunoglobulins rise from ~ day 7 to 21 days after initial infection. IgM does not remain in the body after this initial infectious stage.
- IgG. The body starts building IgG immunoglobulin ~14 days after initial infection and remains for longer periods of time. It is unknown how long IgG remain elevated after exposure to Covid-19.
- At the time of this article, Crush the Curve Idaho offers an IgG test to anyone who wants to be tested for ~$100. Their test may be helpful to determine an immune response, but only 13 days after a positive PCR test or 17 days after symptoms start. It is not reliable for people who never had symptoms. Click HERE to sign up for a test.