One of the most common causes for a sore throat in children and adults is strep throat, a bacterial infection with Group A streptococcus (GAS). The incidence varies with the geographic area, season and age of patients. Children and teenagers are the most susceptible to the infection, especially during late winter and early spring. Because the symptoms of GAS and other illnesses such as tonsillitis are very similar, only thorough strep throat exams and tests can confirm the diagnosis. Laboratory evaluation is very important, due to the fact that strep throat treatment involves powerful antibiotics.
Your doctor will diagnose strep throat based on your medical history, physical exams and tests. The current treatment guidelines recommend that your doctor uses a strep test to confirm the diagnosis, not just a physical exam and analysis of symptoms. However, if the patients has severe symptoms, the treatment may begin before the results of the tests are back. The exams and tests are not painful and patients only feels mild discomfort. A doctor will start with a physical exam and order a test only if the patient has a sore throat lasting more than a week, a fever higher than 100.4° F, a rash, dehydration, blood in mucus or saliva, difficulty swallowing or breathing and white or yellow sports on the throat. The IDSA advised against routine strep throat exams and tests of asymptomatic people who have been in close contact with an infected person.
A throat culture is a test used to find a fungal or bacterial infection in the throat by swabbing a sample and placing it in a special cup (culture) where it can grow under observation. It takes a few days to get the results from the culture. If the bacteria grows, the test is positive and the type of infection is found using chemical tests or a microscope. The culture is negative if there is no bacteria growing in the cup. The doctor may order a throat culture in order to find the cause of a sore throat, or to check if a person is asymptomatic but still carries the bacteria and infects other people. A patient does not have to do anything before strep throat exams and tests. The doctor will ask you to tilt your head back and open your mouth. Then he will press the tongue down with a flat stick and swab the back of your throat to collect a sample.
Rapid strep test
The rapid strep test or rapid antigen strep screen is a test done by a clinician in order to find signs of strep throat. It is one of the most common tests, because the results are available in 10 or 15 minutes. The procedure involves swabbing the throat and tonsils to collect bacteria and see if the strep is responsible for a sore throat. Although this test is performed in-office, there are kits you can use at home. However, the rapid strep test is not 100 percent accurate, and a bad throat secretion can alter the results. The odds of a false positive are lower than the odds of a false negative. In case it is negative, a follow up throat culture is recommended.
Rapid DNA test
This is one of the newest strep throat tests and most accurate. DNA technology is used to detect the bacteria on a throat swab and the results are available in less than one day. This method has the strengths of the other two tests, but none of their weaknesses.