Don’t routinely measure 1,25-dihydroxyvitamin D unless the patient has hypercalcemia or decreased kidney function.
Many practitioners become confused when ordering a vitamin D test. Because 1,25-dihydroxyvitamin D is the active form of vitamin D, many practitioners think that measuring 1,25-dihydroxyvitamin D is an accurate means to estimate vitamin D stores and test for vitamin D deficiency, which is incorrect. Current Endocrine Society guidelines recommend screening for vitamin D deficiency in individuals at risk for deficiency.
Serum levels of 1,25-dihyroxyvitamin D have little or no relationship to vitamin D stores but rather are regulated primarily by parathyroid hormone levels, which in turn are regulated by calcium and/or vitamin D. In vitamin D deficiency, 1,25-dihydroxyvitamin D levels go up, not down.
Unregulated production of 1,25-dihydroxyvitamin D (i.e., sarcoidosis, granulomatous diseases) is an uncommon cause of hypercalcemia; this should be suspected if blood calcium levels are high and parathyroid hormone levels are low and confirmed by measurement of 1,25-dihydroxyvitamin D. The enzyme that activates vitamin D is produced in the kidney, so blood levels of 1,25-dihydroxyvitamin D are sometimes of interest in patients on dialysis or with end-stage kidney disease. There are few other circumstances, if any, where 1,25-dihydroxyvitamin D testing would be helpful.
Serum 25-hydroxyvitamin D levels may be overused, but when trying to assess vitamin D stores or diagnose vitamin D deficiency (or toxicity), 25-hydroxyvitamin D is the correct test.
These items are provided solely for informational purposes and are not intended as a substitute for consultation with a medical professional. Patients with any specific questions about the items on this list or their individual situation should consult their physician.
Members of the Endocrine Society (Society) along with representatives of the American Association of Clinical Endocrinologists (AACE)* formed a joint task force to identify tests or procedures which should only be used in specific circumstances. The task force identified several items for possible inclusion. Subsequent discussions compared the evidence supporting each item, the value of the recommendation to practitioners and the potential for cost savings. Members of the Society’s Clinical Affairs Core Committee and AACE leadership also reviewed the initial list. Using the above criteria, the task force voted for their top five recommendations from the original list. The Society’s Council and AACE’s Board of Directors approved the final list for submission to the Choosing Wisely® campaign.
The Endocrine Society disclosure and conflict of interest policies can be found at www.endocrine.org.
*The American Association of Clinical Endocrinologists withdrew from the Choosing Wisely campaign on May 26, 2015.
Bikle D, Adams J, Christakos S. Primer on the metabolic bone diseases and disorders of mineral metabolism. Washington: American Society for Bone and Mineral Research. c2008.Chapter 28, Vitamin D: production, metabolism, mechanism of action, and clinical requirements. P. 141–9.
Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357:266–81.
Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM; Endocrine Society. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Jul;96(7):1911–30.