Discrepancy or Deficiency? Vitamin D

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Discrepancy or Deficiency? Vitamin D

Vitamin DIt seems that there is a consistent issue with variances of serum and functional measurements of vitamin D.

In short, serum determinations give a static quantitative measurement while functional intracellular assays reflect the long term status of Vitamin D levels.

The results of the serum and functional tests may or may not be in agreement, but this apparently conflicting information is still useful to physicians and patients. If a patient has a low serum level of vitamin D, yet the functional test is normal, these results suggest a short term deficiency of vitamin D and the patient should be repleted. If the serum test is normal, yet the functional test is deficient, the cell may need more vitamin D for optimal function and the patient should be repleted. Therefore both tests are useful in assessing the vitamin D status of patients.

The same principal described for vitamin D may occur with any analyte for which we are reporting functional test results.

What are your thoughts on the difference between functional testing and serum testing?

Posted by Elissa Rodriguez at 12:00 AM