A test in which the infection-causing pathogen is identified from a swab sample taken from the throat. Particularly used in the diagnosis of group A streptococcal pharyngitis.
Indication
- Evaluation of acute pharyngitis and tonsillitis (sore throat)
- Suspicion of group A beta-hemolytic streptococcus (high fever, lymphadenopathy)
- Prevention of acute rheumatic fever and glomerulonephritis
- Investigation of recurrent throat infections
- Screening for diphtheria, gonococcus, or MRSA carriage
- Pharyngitis unresponsive to antibiotic treatment
- Family screening (in scarlet fever cases)
Preparation
- Avoiding any oral intake for 4-6 hours before sample collection is recommended
- Antibacterial gargles and sprays should not be used
- Antibiotic use should be reported to the physician before testing
- The sample is preferably taken in the morning, before breakfast
How it's performed
- The patient opens the mouth wide and extends the tongue
- A sample is collected from the tonsils, posterior tonsillar area, and posterior throat wall using a sterile swab
- The procedure takes 5-10 seconds; a gag reflex may occur
- The presence of streptococci is checked within 10-15 minutes using the rapid antigen detection test (RADT)
- After a negative RADT, the sample is plated on culture media for bacterial culture
- Antibiogram is performed on cultured bacteria
Post-procedure
- If the rapid test is positive, antibiotic treatment is started immediately
- Culture results are reported within 24-48 hours
- If streptococcus is positive, a 10-day antibiotic course is completed
- If family members have symptoms, testing may also be recommended for them
Risks
- Brief gag reflex during sample collection
- Mild discomfort in cases with sensitive tonsils
- Fear and resistance in children
- False negative result (insufficient sample)
FAQ
What is the difference between rapid testing and culture?
The rapid antigen test gives results in 10-15 minutes but has limited sensitivity. Culture is the gold standard; results are available in 24-48 hours and also show antibiotic susceptibility.
Is culture required for every sore throat?
No. Most sore throats are viral and do not require antibiotics. Culture is recommended in cases with high fever, white exudates, and lymph node swelling.
Is sample collection painful?
It is not painful. Only a gag sensation may occur when the swab touches the tonsils; the procedure lasts a few seconds.
What happens if streptococcal infection is not treated?
Late complications such as acute rheumatic fever, heart valve disease, and kidney inflammation (glomerulonephritis) may develop. Treatment is therefore important.
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