What are the recommended guidelines for testing vitamin D levels in adults at risk of deficiency?

Recommended guidelines for testing vitamin D levels in adults at risk of deficiency:

• Routine monitoring of serum 25-hydroxyvitamin D (25[OH]D) levels is not routinely needed in adults, even those at risk of deficiency.
• Testing serum 25(OH)D levels should be considered only if the adult has symptoms of vitamin D deficiency, a malabsorption disorder, suspected poor compliance with vitamin D medication, or if they are prescribed antiresorptive therapy and have extremely low baseline vitamin D levels.
• Testing is also appropriate if the adult requires sequential doses of potent antiresorptive agents such as zoledronate, denosumab, or teriparatide.
• If serum 25(OH)D is found to be <50 nmol/L, adherence to treatment should be assessed and referral to a specialist for investigation of an underlying cause should be arranged.
• If serum 25(OH)D is >50 nmol/L, advise on lower dose maintenance vitamin D treatment.
• Adjusted serum calcium levels should be checked to detect hypercalcaemia or unmasked primary hyperparathyroidism in people on vitamin D therapy.
• Testing vitamin D status is recommended only when there is a clinical reason, such as symptoms or very high risk, not for routine screening.

These recommendations aim to avoid unnecessary testing and focus on clinical indications for vitamin D measurement in adults at risk of deficiency.

References: NICE CKS, NICE