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Streptococcal screen

Definition

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

Alternative Names

Rapid strep test

How the test is performed

The test requires a throat swab. It takes about 7 minutes. The swab is tested to identify group A streptococcus, the cause of strep throat.

How to prepare for the test

There is no special preparation. Inform the health care provider if you are taking, or have recently taken, antibiotics.

How the test will feel

Your throat will be swabbed in the area of the tonsils. This may make you gag.

Why the test is performed

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

  • Fever
  • No coughing
  • Tender and swollen glands in the front of the neck
  • White or yellow spots on the tonsils

Normal Values

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

If your health care provider still feels that you may have strep throat, a throat culture will be done.

What abnormal results mean

A negative strep screen most often means Group A streptococcus is present, and confirms strep throat.

At times, the test may be positive even if you do not have strep. This is called a false-positive result and is more likely if you have a fever or the symptoms of strep throat.

What the risks are

There are no risks.

Special considerations

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

References

Wessels MR. Clinical practice. Streptococcal pharyngitis. . 2011;364(7):648-655.

Weber R. Pharyngitis. In: Bope ET, Kellerman RD, eds. . 1st ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 1.

Nussenbaum B, Bradford CR. Pharyngitis in adults. In: Flint PW, Haughey BH, Lund LJ, et al, eds. . 5th ed. Philadelphia, Pa: Mosby Eslevier; 2010:chap 13.

Encyclopedia content is provided as information only and not intended to replace the advice and instruction from your personal physician.