Blood-tests Explained


Disclaimer:

This website is intended to assist with patient education and should not be used as a diagnostic, treatment or prescription service, forum or platform. Always consult your own healthcare practitioner for a more personalised and detailed opinion

Strep Throat Test


At a Glance

Why Get Tested?

To determine if your sore throat is "strep throat" that is caused by group A streptococcus (GAS) bacteria

When to Get Tested?

When you have a sore throat that starts quickly and lasts more than a week and/or other symptoms such as a fever of 101° F or higher, or reddened throat and/or tonsils with white or yellow patches or streaks

Sample Required?

A swab rubbed against the back of your throat and tonsils

Test Preparation Needed?

None

The Test Sample

What is being tested?

The bacteria Streptococcus pyogenes, also known as group A beta-hemolytic streptococcus or group A streptococcus (GAS), causes "strep throat," the most common bacterial cause of inflammation and soreness of the back of the throat (pharyngitis). Strep throat tests identify the presence of these bacteria as the cause of a sore throat.

While most sore throats are caused by a virus and will resolve without treatment within a few days, some people with sore throats have strep throat. Strep throat is most common in children ages 5 to 15 years old. It is important that these bacterial strep infections be promptly identified and treated with antibiotics.

Strep throat is contagious and can spread when an infected person coughs or sneezes and other people come into contact with the droplets or mucus. Touching the face, eyes or mouth after touching something that has these droplets on it can spread the infection. The best way to avoid getting strep throat is to wash hands thoroughly and often and avoid sharing items like utensils or cups. A person who has a sore throat should wash their hands often and cover their mouth with a tissue or sleeve when coughing and sneezing.

If strep throat is not diagnosed and treated, secondary complications may develop, especially in children. These complications may include rheumatic fever, which can damage the heart, and glomerulonephritis, which affects the kidneys. Because streptococcal infections are routinely diagnosed and treated, these complications are rare in the United States now, but they do still occur.

A rapid strep test and/or a throat culture is used to diagnose group A streptococci as the cause of symptoms and allows the health practitioner to prescribe the proper antibiotics for treatment. (Read more on the "The Test" tab.)

How is the sample collected for testing?

A health practitioner uses a tongue depressor to hold down a person's tongue and then inserts a special swab into the mouth and rubs it against the back of the throat and tonsils. The swab may be used to do a rapid strep test in a doctor's office or clinic, or it may be sent to a laboratory. A second swab may be collected along with the first one. This extra sample is used to perform a throat culture as a follow-up test, when necessary.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed. The test should be performed before antibiotics are prescribed.

The Test