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Streptococcal screen

A streptococcal screen is a test to detect group A streptococcus. This type of bacteria is the most common cause of strep throat.

How the Test is Performed

The test requires a throat swab. The swab is tested to identify group A streptococcus. It takes about 7 minutes to get the results.

How to Prepare for the Test

There is no special preparation. Tell your health care provider if you are taking antibiotics, or have recently taken them.

How the Test will Feel

The back of your throat will be swabbed in the area of your tonsils. This may make you gag.

Why the Test is Performed

Your provider may recommend this test if you have signs of strep throat, which include:

  • Fever
  • Sore throat
  • Tender and swollen glands at the front of your neck
  • White or yellow spots on your tonsils

Normal Results

A negative strep screen most often means group A streptococcus is not present. It is unlikely that you have strep throat.

If your provider still thinks that you may have strep throat, a throat culture will be done in children and adolescents.

What Abnormal Results Mean

A positive strep screen most often means group A streptococcus is present, and confirms that you have strep throat.

Sometimes, the test may be positive even if you do not have strep. This is called a false-positive result.

Risks

There are no risks.

Considerations

This test screens for the group A streptococcus bacteria only. It will not detect other causes of sore throat.

Alternative Names

Rapid strep test

References

Bryant AE, Stevens DL. Streptococcus pyogenes. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 197.

Nussenbaum B, Bradford CR. Pharyngitis in adults. In: Flint PW, Haughey BH, Lund V, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 6th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 9.

Stevens DL, Bryant AE, Hagman MM. Nonpneumococcal streptococcal infections and rheumatic fever. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 274.

Tanz RR. Acute pharyngitis. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 409.

Review Date 1/23/2020

Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.