Vitamin D Test

Test Overview

A vitamin D, Opens dialog test measures the amount of vitamin D in the blood. The vitamin D test is also called the 25-hydroxy vitamin D, or 25(OH)D, test.

Your body needs vitamin D to absorb calcium, Opens dialog. Calcium keeps your bones and muscles healthy and strong. If your muscles don't get enough calcium, they can cramp, hurt, or feel weak. You may have long-term (chronic) muscle aches and pains. If you don't get enough vitamin D throughout life, you are more likely to have thin and brittle bones (osteoporosis, Opens dialog) in your later years.

Children who don't get enough vitamin D may not grow as much as others their age. They also have a chance of getting a rare disease called rickets, Opens dialog.

Your body uses sunshine to make its own vitamin D. Vitamin D is found in foods such as egg yolks, liver, and saltwater fish. It is added to many food products, such as milk and cereals. You can also get it as supplements, often combined with calcium.

The vitamin D test is usually done in a doctor's office or a lab. Or you may be able to buy an at-home version of the test. Discuss the benefits and risks of at-home testing with your doctor before you buy one of these tests.