Vitamin D

About the Vitamin D test

Vitamin D testing measures the level of this essential substance in your blood. It is used to diagnose vitamin D deficiencies or monitor treatment for a known deficiency. The main function of vitamin D is to aid in calcium absorption during bone formation. Maintaining adequate levels of vitamin D supports healthy bones. In addition, vitamin D has anti-inflammatory and other properties that play a role in maintaining normal muscle, immune, and nervous system functions.

Purpose of the test

Vitamin D testing shows whether your vitamin D levels are within a healthy range. Levels of vitamin D that are too low or too high can lead to serious health issues.

Lower than ideal vitamin D levels are common, especially among the elderly, individuals with limited sun exposure, people who are obese, those with darker skin pigmentation, people with kidney or liver diseases, and those who have problems absorbing nutrients because of digestive disorders.

Although rare, vitamin D levels can also be too high, called vitamin D toxicity. This can occur from ingesting too many vitamin D supplements or having certain health conditions.