How To Swab a Throat for Testing

In patients with tonsillopharyngitis, a throat swab may be needed primarily to diagnose:

• Group A beta-hemolytic streptococci (GABHS) infection

• Gonococcal infection

Gonococcal pharyngitis may be suspected in patients with known or possible exposure to gonorrhea (eg, recent oral-genital contact).

Criteria suggestive of need for testing for GABHS pharyngitis include the presence of ≥ 2 of the following:

• Tonsillar exudate

• Tender lymphadenopathy

• Fever (on examination or by history)

• Absence of cough

Threshold for GABHS testing may be lower in patients at increased risk because of diabetes or immunocompromise.

Throat swabs are also sometimes tested if COVID-19 is suspected. Throat swabs may also be useful for diagnosing rarer causes of pharyngitis, including Fusobacterium necrophorum (Lemierre syndrome), Arcanobacterium haemolyticum, and Corynebacterium diphtheria.

• None

Caution is advised when swabbing the throats of patients with known bleeding diathesis, as forceful swabbing may precipitate bleeding.

• None

The swab may cause brief, minor gagging.

• Sterile swab

• Tongue depressor

• Light source; flexible lamp or head-mounted light (optional)

Use swabs supplied with the specific test kit being used or by the facility's laboratory. If none are supplied, use a swab with a plastic or wire shaft and a rayon, Dacron, or calcium alginate tip. Avoid swabs with wooden shafts and/or cotton tips because these materials may interfere with certain tests. 

• The tonsils are located along the sides of the posterior oropharynx. They lie between the anterior and posterior pillars of the throat.

Anatomy of the Oropharynx

3D Model

• Sitting position with the head tilted back slightly.

• Explain the procedure to the patient, including that they may gag briefly.

• Wear gloves and eye protection, and if COVID-19 (or any other airborne infection) is under consideration, gown, N95 respirator, and face shield.

• Position the patient and light source to illuminate the posterior oropharynx.

• Have the patient open the mouth and relax the tongue by saying "aaaah."

• Press the tongue down using a tongue depressor.

• Gently rub the swab against both tonsils and the posterior pharynx.

• Place the swab in the culture medium, transport medium, or sterile test tube.

• Follow-up on test results.

• Touching the swab to the tongue or oral mucosa (sides of the mouth)

• Not swabbing all 3 sites in the pharynx

• Proceed swiftly because the patient will likely gag.

• Having the patient stick out the tongue actually stiffens it and can make it harder to see the pharynx.