Vitamin D Deficiency

How is a vitamin D deficiency diagnosed?

All it takes is a simple blood test to find out if you are deficient in vitamin D, but determining the optimal level is not quite as simple. There is a lot of controversy about what the optimal levels and deficient levels are. The test will measure your 25(OH)D level. The Institute of Medicine set the guidelines for serum (blood) 25(OH)D levels to be as follows:

  • Deficiency: 25(OH)D level BELOW 12 ng/mL
  • Inadequate: 25(OH)D level BETWEEN 12-20 ng/mL
  • An adequate 25(OH)D level is between 20-50 ng/mL
  • Excessive: 25(OH)D level over 50 ng/mL

Many believe that 30 ng/mL should be the minimum for an adequate level. According to the NHANES national survey the average vitamin D level has dropped from 30 ng/mL in 1988-1994 to 24 ng/mL in 2001-2004. The percentage of those below 10 ng/mL has increased from 2% to 6%, and the percentage with levels of 30 or above has decreased from 45% to 23%. With the levels changing at this rate, this really has become an epidemic.

Reviewed on 7/14/2014