Strep A Test Test
A strep A test checks for group A Streptococcus bacteria, which cause strep throat and other infections. The test helps determine if a sore throat is from strep (needing antibiotics) or a virus (which goes away on its own).
What this test measures
The test looks for group A Streptococcus bacteria or their antigens in a throat swab. A rapid strep test detects antigens in 10-20 minutes, while a throat culture grows the bacteria and takes 24-48 hours.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
A positive result (either rapid test or throat culture) means you or your child has strep throat or another strep A infection.
Lower-than-normal results
A negative throat culture means your symptoms are not caused by strep A bacteria. Your provider may order more tests to find the cause.
Frequently asked questions
How long does it take to get results from a strep A test?
A rapid strep test gives results in 10-20 minutes. A throat culture takes 24-48 hours.
What happens if the rapid test is negative but my provider still thinks it's strep?
Your provider may order a throat culture. If you haven't already provided a sample, you will get another swab test.
Do I need antibiotics if I test positive but have no symptoms?
No. Someone who tests positive but has no symptoms (a 'carrier') usually does not need antibiotics.
Can I get strep throat more than once?
Yes. Having strep throat does not protect you from getting it again in the future.
How can I prevent spreading group A strep?
Cover your mouth and nose when coughing or sneezing, wash hands often with soap and water for at least 20 seconds, and clean frequently touched surfaces.
Related lab tests
Sources
- MedlinePlus: Strep A Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.