The present invention relates to a method of determining the microbial bioburden in a wound (in particular a diabetic ulcer) in a test subject, the method comprising the step of measuring the level of a cytokine in a wound sample, wherein a cytokine level lower than a reference level indicates a significant microbial bioburden in the wound (or a cytokine level higher than a reference level indicates an insignificant microbial bioburden in the wound). The invention provides methods of diagnosis, prognosis and treatment of wound infection, and devices and kits for use in such methods.