If you need to be tested for
strep throat, the choice between a rapid strep test
and a throat culture may not be clear. It may be helpful to discuss with your
doctor the advantages and disadvantages of each.
Rapid strep test
Results from a rapid strep
test are available within 10 to 15 minutes. Results from a throat culture may
take 1 to 2 days. The faster speed of the results from rapid strep testing
gives it some advantages over throat culture when the results of the rapid test
are positive:
- Antibiotic treatment can be started
immediately. You do not have to wait 1 to 2 days for test results from a throat
culture.
- You are contagious for a shorter period of time and thus
able to return to school or work sooner.
But the rapid strep test is not as accurate as a throat
culture. The rapid strep test can give negative results even when strep
bacteria are present. If the results of a rapid strep test are negative, many doctors may recommend doing a throat culture to
confirm that you do not have strep throat.
- Having a second test costs more than just
having a throat culture at the beginning.
- You will still have the
1- to 2-day waiting period for results.
Throat culture
If you have a throat culture instead
of a rapid strep test, you will need only one test because the results of a
throat culture are usually very accurate. If the results are negative, you will
not need further testing or antibiotics. If the results are positive, you can
start antibiotic treatment immediately. But you could have started antibiotic
treatment a day or two earlier if you had a rapid strep test.
There is also some debate over when to begin treatment. Although
immediate treatment decreases the time the person is able to pass on the
infection, it may reduce the body's natural defense (immune) response to the
infection. If 1 to 2 days pass before beginning treatment, the body has a
chance to build up its disease-fighting mechanism. Antibiotic treatment will
still help prevent
rheumatic fever when started up to 9 days after
symptoms start.1
So some experts feel
that it is better to have a throat culture than a rapid strep test because the
culture imposes a 1- to 2-day waiting period before the person begins taking
antibiotics (if they are needed).