A Vitamin B7 (biotin) blood test measures the levels of biotin in the blood. Biotin, also known vitamin H, is a nutrient that is important for the metabolism of carbohydrates, proteins, and fats. It is also necessary for the proper function of the skin, hair, and nails. Biotin is found in a wide variety of foods, including egg yolks, nuts, and legumes, and is also available as a dietary supplement.

The results of a Vitamin B7 blood test can help a healthcare provider diagnose and monitor conditions related to biotin levels, such as biotin deficiency or excess, liver problems, and malnutrition. The test can also be used to monitor the effectiveness of biotin supplementation. Biotin deficiency is rare and usually only occurs in people with certain medical conditions or who are taking certain medications that interfere with biotin absorption. Symptoms of biotin deficiency include hair loss, skin rashes, and muscle pain. It is important to treat biotin deficiency promptly to prevent these complications.