Appropriate Use of Vitamin D Testing | July 2021 | Clinical Corner

Appropriate Use of Vitamin D Testing

Vitamin D deficiency is common in many populations, particularly in patients at higher latitudes, during winter months and in those with limited sun exposure. Over the counter Vitamin D supplements and increased summer sun exposure are sufficient for most otherwise healthy patients. Laboratory testing for Vitamin D levels with 25-OH Vitamin D testing is appropriate only in higher risk patients when results will be used to institute more aggressive therapy (e.g., osteoporosis, chronic kidney disease, malabsorption, some infections, obese individuals).

Serum levels of 1,25-dihydroxyvitamin 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. This is a significantly more expensive test with very limited indications: ESRD and complex hypercalcemia/ PTH disorders.

Expert recommendations (Choosing Wisely- ASCP 2013; Choosing Wisely- Endocrine Society 2013):

  • Don’t perform population-based screening for 25-OH Vitamin D deficiency.
  • Reserve screening for 25-OH Vitamin D deficiency in individuals at risk for deficiency.
  • Don’t routinely measure 1,25-dihydroxyvitamin D unless the patient has hypercalcemia or decreased kidney function.

 Indications for 25-OH Vitamin D testing based upon Endocrine Society guidelines:


  • Risk for osteopenia or demonstrated fractures
  • Osteoporosis, osteomalacia, and other bone diseases
  • Chronic kidney disease stage III or greater
  • Parathyroid or other endocrine or metabolic disorder
  • Individuals with malabsorption and risk of malnutrition (e.g., celiac disease, Ulcerative colitis, Crohn’s Disease, cirrhosis, cholestatic liver disease, pancreatic insufficiency)
  • Long term anticonvulsant or glucocorticoid therapy
  •  Children on proton pump therapy > 6 months

Indications for 1,25-dihydroxyvitamin D testing:


  • End Stage Renal Disease
  • Complex hypercalcemia/ PTH disorders


Special thanks to Dr. Tim Hannon, CEO Healthcare Forward and Chairman of the MHC High Value Care Committee for the clinical content of the clinical corner.