The medical term for gray nails is onychomycosis. Detecting whether onychomycosis is onychomycosis can be clarified by perfecting fungal microscopy and fungal culture. 1. Fungal microscopy: it is a kind of examination technique to observe the fungal form under the microscope by taking the hair, dander, nail clippings, etc. which are suspected to be fungal. This means of examination has diagnostic significance in detecting fungal diseases. 2. Fungal culture: This is an examination in which the collected specimen is placed in a culture medium to observe whether the specimen has a fungal shape. Fungal culture can effectively determine whether or not a fungal infection has occurred, and can also clarify which kind of fungal infection, is a common clinical examination method. In the case of suspected gray nails, it is recommended to seek medical examination in time to avoid delaying the condition.