1,25-dihydroxyvitamin D3 in serum (serum calcitriol)

Indications

• differentiating primary hyperparathyroidism from hypercalcemia of malignancy
• distinguishing vitamin D-dependent & vitamin D-resistant rickets
• monitoring vitamin D status in patients with chronic renal failure
• assessing compliance with calcitriol therapy

Reference interval

• 16-65 pg/mL (42-169 pmol/mL)

Increases

• calcinosis secondary to tumor
• primary hyperparathyroidism
• idiopathic hypercalciuria
• sarcoidosis
• tuberculosis
• lymphoma (some cases)
• normal growing children
• pregnant & lactating women

Decreases

• azotemic chronic renal failure*
• hypoparathyroidism
• pseudohypoparathyroidism
• vitamin D-dependent rickets
• vitamin D-resistant rickets (familial hypophosphatemia)
• postmenopausal osteoporosis
• tumor-induced osteomalacia
• adolescents with insulin-requiring diabetes
• suboptimal 1,25-dihydroxyvitamin D levels associated with increased mortality

* 1,25-dihydroxyvitamin D3 is NOT detectable in serum of anephric patients.

Methods

• column chromatography with RIA

Specimen

• serum or plasma (heparin)
• stable at room temp for 72 hours
• store frozen; stable indefinitely at -20 degrees C

Notes

• 1,25-dihydroxyvitamin D3 is NOT a good measure of overall vitamin D status

More general terms

• 1,25-dihydroxyvitamin D in serum

Additional terms

• calcitriol; 1,25-dihydroxycholcalciferol; 1,25-dihydroxyvitamin D3

Patient information

1,25-dihydroxyvitamin D3 in serum patient information