Active Vitamin D (Calcitriol)

What is Active Vitamin D (Calcitriol)?

Calcitriol is the biologically active form of vitamin D, produced mostly in the kidneys from the stored 25-hydroxy form (the one most blood tests measure). It binds the vitamin D receptor and directly regulates calcium absorption in the gut and calcium handling in the kidneys.

What might a high or low Active Vitamin D (Calcitriol) mean?

Unlike 25-OH vitamin D, which reflects long-term stores, calcitriol reflects current regulation. It is usually ordered to investigate calcium-metabolism problems, suspected vitamin D resistance, or some forms of sarcoidosis and granulomatous disease where calcitriol can be inappropriately high even when 25-OH vitamin D is normal.

What is the typical reference range for Active Vitamin D (Calcitriol)?

The general-population reference range shown here is 48 – 190 pmol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.

What can affect Active Vitamin D (Calcitriol)?

It may be higher with: Sarcoidosis and other granulomatous diseases, Some lymphomas, Primary hyperparathyroidism, Pregnancy, Vitamin D intoxication. It may be lower with: Chronic kidney disease (reduced renal activation), Severe 25-OH vitamin D deficiency, Hypoparathyroidism, Some inherited forms of rickets.