A streptococcal screen is a test to detect group A streptococcus, 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, the cause of strep throat. It takes about 7 minutes to get the results.
How to Prepare for the Test
There is no special preparation. Tell your doctor if you are taking, or have recently taken antibiotics.
How the Test will Feel
The back of your throat will be swabbed in the area of the tonsils. This may make you gag.
Why the Test is Performed
Your doctor may order this test if you have signs of strep throat, which include:
- Sore throat
- Tender and swollen glands at the front of your neck
- White or yellow spots on your tonsils
A negative strep screen most often means Group A streptococcus is not present. It is unlikely that you have strep throat.
If your doctor still thinks that you may have strep throat, a throat culture will be done.
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 and is more likely if you have a fever or other symptoms of strep throat.
There are no risks.
This test screens for the group A streptococcus bacteria only and will not detect other causes of sore throat.
Rapid strep test
Nussenbaum B, Bradford CR. Pharyngitis in adults. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Cummings Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, PA: Elsevier Mosby; 2010:chap 13.
Weber R. Pharyngitis. In: Bope ET, Kellerman RD, eds. Conn's Current Therapy 2012. 1st ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 1.
Wessels MR. Clinical practice. Streptococcal pharyngitis. N Engl J Med. 2011;364(7):648-655. PMID: 21323542 www.ncbi.nlm.nih.gov/pubmed/21323542.
Update Date 5/12/2014
Updated by: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.