How is a throat infection diagnosed?

Child's throat being examined

Your doctor may examine your child's throat and tonsils for signs of infection. Image: Ilya Andriyanov /

Your doctor may ask you some questions about your symptoms, including if you:

  • have had a cold or flu (influenza) recently
  • are taking any medicines
  • have any other medical conditions (e.g. asthma).

If your sore throat is caused by the cold or flu viruses, you will also have other cold or flu symptoms such as a cough, aches and pains and a runny nose.

Your doctor may examine your throat and look at your tonsils to see if they are inflamed or if there are any other signs of infection (e.g. white pus or white spots on your tonsils).

A diagnosis of a bacterial infection (caused by Streptococcus pyogenes) is more likely if you have the following symptoms:

  • fever (a temperature of 38.5°C or higher)
  • no cough
  • swollen ‘glands’ (lymph nodes) in your neck
  • white spots or pus on your tonsils (tonsillitis).

Laboratory tests

Your doctor may use a sterile cotton swab to take a small sample of cells from your tonsils and the back of your throat, which can be sent to a laboratory to find out what is causing the infection. This can help your doctor to decide if bacteria are causing your infection, whether you need antibiotics, and if so, which antibiotic.Find out more about the causes, symptoms, and treatment of sore throats.

  • Antibiotic Expert Group. Therapeutic guidelines: Antibiotic; Pharyngitis and/or tonsillitis. Melbourne: Therapeutic Guidelines Ltd; 2012.
  • NHS Choices. Sore throat — diagnosis. London: NHS, 2010. (accessed 4 May 2012).