Your doctor will likely be able to diagnose a boil or carbuncle simply by looking at it. He or she might suggest sending a sample of the pus to a lab for testing. This may be useful if you have recurring infections or an infection that hasn't responded to standard treatment.

Many varieties of the bacteria that cause boils have become resistant to certain types of antibiotics. So lab testing can help determine what type of antibiotic would work best in your situation.

July 13, 2016
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  2. Boils and carbuncles. National Health Service. http://www.nhs.uk/conditions/boils/pages/introduction.aspx. Accessed June 15, 2016.
  3. Habif TP. Bacterial infections. In: Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Philadelphia, Pa.: Elsevier; 2016. http://www.clinicalkey.com Accessed June 20, 2016.
  4. Adams JG. Skin and soft tissue infections. In: Emergency Medicine: Clinical Essentials. 2nd ed. Philadelphia, Pa.: Saunders Elsevier; 2013. http://www.clinicalkey.com. Accessed June 17, 2016.
  5. Kliegman RM, et al. Cutaneous bacterial infections. In: Nelson Textbook of Pediatrics. 20th ed. Philadelphia, Pa.: Elsevier; 2016. http://www.clinicalkey.com. Accessed June 16, 2016.