A blood test for herpes simplex usually does not require fasting, but it is recommended to try not to eat too much greasy food. Herpes simplex virus is a common skin disease, mostly occurring at the junction of skin and mucous membranes, and is mainly characterized by clustered blisters, which can cause skin and mucous membrane infections, and is one of the dermatological examination items. The process of checking antibodies has nothing to do with metabolism, absorption and other factors, eating or not will not affect the results of the test, so generally do not need to fasting. Although the blood test for herpes simplex does not require fasting, it is recommended that patients do not eat too much greasy food, as greasy food may lead to high blood lipids and thus affect the test results. If the patient needs to check the liver function, blood sugar and other items at the same time, then it is necessary to fasting. When checking for herpes simplex, patients are advised to ask their doctors for clarification, and if they do not need to check for other diseases at the same time, they generally do not need to fast, and cooperate with the doctor’s recommendations for the examination.