Screening for yeast infection (candidiasis) begins with a medical history noting symptoms and a physical examination. When the affected area is the skin, mouth or nails, the doctor can diagnose a yeast infection by observation. He may take a small scraping of skin to develop a culture. Adults and children with candidiasis of the skin may also be tested for diabetes and other immune system disorders.
In the case of vaginal yeast infection, a pelvic examination will show redness or swelling of the vagina or vulva. The doctor may also discover white spots on the walls of the vagina and cracks in the skin on the vulva.
Other tests for yeast infection in the vagina include the wet prep test, vaginitis test or wet mount test, in which the doctor examines the vaginal discharge through a microscope to detect infections of the vagina. If the condition does not respond to treatment or recurs often, a culture may be taken to identify the specific cause of the infection.