Your GP will be able to diagnose a boil or carbuncle by looking at it. Further testing is usually only required if you have:
- a boil or carbuncle that doesn't respond to treatment; it may be caused by bacteria other than staph bacteria
- multiple boils or carbuncles
- a weakened immune system, due to a condition, such as diabetes, or you're having a treatment, such as chemotherapy
In these circumstances, your GP will probably use a cotton swab to take a tissue sample from the boil so that it can be examined under a microscope.
You may also be referred for a blood test to see if you have an underlying health condition, such as diabetes (if diabetes hasn't previously been diagnosed), which could be increasing your risk of developing boils and carbuncles.
