 [ Symptoms ] what exams and tests help doctors to evaluate or test people for athletes foot [ Disease ] in most cases your doctor can diagnose athlete is foot tinea pedis by looking at your foot he or she will also ask about your symptoms and any previous fungal infections you have had if your symptoms look unusual or if a previous infection has not responded well to treatment your doctor may collect a skin or nail sample by lightly scratching the skin with a blade or the edge of a microscope slide or by trimming a nail he or she will examine the skin and nail samples using laboratory tests including koh potassium hydroxide preparation to confirm the presence of fungi fungal culture to identify the type of fungus present in rare cases a skin biopsy will be done by removing a small piece of skin that will be looked at under a microscope webmd medical reference from healthwise this information is not intended to replace the advice of a doctor healthwise disclaims any liability for the decisions you make based on this information © 1995 2011 healthwise incorporated healthwise healthwise for every health decision and the healthwise logo are trademarks of healthwise incorporated