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Parents who suspect their child may have strep throat should consult their child’s pediatrician. They may also be referred to an ear, nose and throat specialist.

A physical examination should include a visual inspection of a child’s throat. A tongue depressor may be used to enable clear viewing of the back of the throat. A medical history may be compiled, which can include questions about the frequency of throat infections in the child.

Strep throat cannot be diagnosed strictly by symptoms and physical examination. The only way to identify the presence of strep throat is through the following diagnostic tests:

• Rapid strep test (also called the rapid antigen test). A physician will swab the back of the child’s throat for a tissue sample. This can be analyzed and results are typically available in minutes. It can detect the strep bacteria in 75 to 85 percent of strep throat cases, according to the American Academy of Family Physicians (AAFP).
  
  
• Throat culture. A physician swabs the child’s throat (similar to the method used for the rapid strep test) and the tissue sample is then sent to a laboratory for analysis. Results are generally not available for at least a day or two.

Generally, both tests are performed, particularly if the rapid strep test is negative. The rapid strep test allows treatment to begin immediately (if strep throat is detected) and the throat culture is used to confirm this result. Occasionally, the throat culture (a more sensitive test) may detect a strep throat infection that was missed during the rapid strep test. 

A new diagnostic test has been developed that uses DNA technology, called the rapid DNA test. It provides results within a few hours, and may be more sensitive than the rapid antigen test. Parents should consult with the physician about the availability of this test.

Family members who are not currently displaying symptoms of strep throat will sometimes receive a rapid strep test and throat culture to help determine if they are carriers.