are direct tests and indirect tests.
- Direct PCR tests are more accurate. Direct tests look
for the virus or portions of the virus itself.
Direct tests are polymerase chain reaction tests (PCR)
that react when viral RNA is present. Just like most tests, PCR tests are very accurate, but the accuracy depends on
the amount and quality of the specimens that are tested and the type of RNA the test examines.
is a viral test to see if you have the infection right now. This is a PCR (polymerase chain reaction) RNA test that looks
for bits of the virus. In order to get an appropriate sample with a swab that may be placed in the nose, the throat or possibly
just in the mouth. This testing takes several hours after the swab makes it to the special lab that has the equipment to run
the sample. These are the tests that were significantly backed up at some of the large labs. It took several days to get the
reports, but is now down to about 48 hours. The test is to help determine treatment for individuals.
+ A positive tests tells us a person is infected and should be watched carefully for the possible
development of deadly symptoms. While most (over 80%) of us do well and have symptoms mostly like a cold, some may become
extremely ill, with high fever, or shortness of breath or other symptoms that should lead them to the hospital.
> False positive PCR tests are extremely rare. There may be false positives
if the test is too broad. The current PCR tests are generally tuned very tightly to the SARS-CoV-2 and are nearly 100%
- On the other hand a negative test doesn't
mean anything because it tells us only that a person was negative at the moment in time the test was performed
and says nothing about what may happen twenty minutes later when they may be exposed at the grocery. It is not helpful for
any decision-making purpose. If people are confused about the test and think a negative test is predictive in some way they
are mistaken. No medical or workplace decision should ever be based on a report of a negative test.
negatives (A person truly has the virus but their test is negative) may occur if there is too little test material
(generally mucus from the nose or saliva from the mouth) or if the test material is too diluted. Self-testing has more false
negatives because often an individual does not put the swab in deep enough, or leave it in for enough material to be picked
up on the swab. Since false negative corona virus tests may occur, people with continuing symptoms are asked to follow
with their health care provider.
- Indirect tests look for antigens (proteins produced by the
virus) and/or antibodies (immune components made by the human immune system).
These tests have a lower accuracy rate because there may be cross-reacting (similar) antigens or antibodies
from colds or other corona viruses.
These are blood tests, usually
have a faster reporting time and have a higher number of false positives and false negatives or erroneous tests. While the
FDA has authorized some of these tests to be marketed, none are actually approved.