Truth About Vitamin D: Vitamin D Tests

Will a vitamin D test tell me if I need more vitamin D?

That depends on whom you ask. As part of your regular blood test, your doctor can order a test for 25-hydroxyvitamin D (25-OHD).

Even so, most experts agree that anyone with a 25-OHD level of less than 15 ng/ mL or 37.5 nmol/L (depending on the units reported by a lab) needs more vitamin D. A 2002 study found that 42% of African-American women of childbearing age had vitamin D levels below 15 ng/mL.

The IOM committee says that people are at risk of vitamin D deficiency at 25-OHD levels below 30 nmol/L (12 ng/mL), and that some people -- but not everyone -- may be at risk of vitamin D deficiency at 25-OHD levels from 30 nmol/L up to 50 nmol/L (12-20 ng/mL).

The Vitamin D Council considers the ideal 25-OHD level to be between 40 ng/ mL and 70 ng/mL. But the IOM says there is no evidence of increased benefit at levels above 30 ng/mL, and that "there may be reason for concern" at levels above 50 ng/mL.

"There is a critical public health and clinical practice need for consensus cut- points for serum 25-OHD," the IOM committee states.

Next: Which foods contain vitamin D?

1 2 3 4 5 6 7 8 9

Read more on: osteoporosis, features