Diseases

Obtaining a specimen is the same whether your doctor will do a throat culture or rapid test for strep. A cotton swab (similar to a Q-tip) is quickly rubbed over both tonsils as well as the back wall of the mouth (the posterior pharynx). It is important to avoid contact with other structures inside the mouth such as the tongue or cheeks. The swab is then placed in a specialized container and the rapid test performed. Many people find that obtaining the swab produces a gagging sensation. However, since the entire swabbing process lasts less than five seconds this inconvenience is minimal.

There are several manufactures of rapid strep tests. Each manufacturer has designed their test to respond only to the presence of the particular streptococcal bacteria (Group A) responsible for strep throat. Other bacteria which are less much less likely to cause sore throats are not identified by the rapid strep test.

• The test will not detect viral causes of sore throat.
• A positive test response occurs when a reaction occurs between a protein on the surface of strep bacteria and chemicals in the test materials. Either living or dead strep bacteria will produce a positive reaction.
• Most rapid strep tests have a sensitivity of 95%, meaning that the test will be positive in 95 of 100 patients who are documented to have strep throat via throat culture obtained at the same time. Since 5 of 100 patients with strep throat will be missed using a rapid strep test, all negative swab specimens should be sent for culture to confirm the absence of strep bacteria.
• A positive culture requires antibiotics.
• The rapid strep test has a 98% specificity. This means that 98 of 100 positive tests correctly indicate the presence specifically of Group A streptococcus bacteria; 2 of 100 positive results are "false positives" - indicative of similarities between various surface proteins found on strep bacteria and other non-strep bacteria found in the mouth.

The rapid strep test is a quick and accurate diagnostic tool used to determine whether or not strep bacteria are present in the patient's throat. The same test may be used to evaluate for the presence of Streptococci in other infected areas (for example, perianal infection in either gender, or vulvar infection in pre-pubertal girls).

The traditional test for a strep throat has been a throat culture. The major drawback of a throat culture is that the results take two to three days due to the time necessary to allow enough GAS bacteria to grow to enable accurate identification.

Patients benefit both immediately and potentially in the long-term by rapid confirmation of streptococcal cause of their sore throat. Antibiotic treatment provides a quicker reduction of symptoms, shortens the duration of illness and quickly, and efficiently eliminates the possibility of spread of infection to others.

• Although rare, serious consequences of streptococcal infections do occur. Rheumatic fever is associated with heart, joint and nervous system damage and is preventable by rapid treatment of strep disease.
• Serious kidney disease that may result in kidney failure may also be a consequence of streptococcal infection.
• A throat infection due to strep needs antibiotic therapy initiated as rapidly as possible. The rapid strep test facilitates this goal.

By comparison with culture methods, a rapid strep test is much quicker and can produce results within minutes.