Lab test

Vitamin D 25-Dihydroxy (Calcitriol) Test

This blood test measures vitamin D 25-dihydroxy (calcitriol), the active form of vitamin D.

Typical price

From $170

Results

1-3 business days

Preparation

See preparation notes below

Sample

Blood draw or sample collection at a local center

This blood test measures vitamin D 25-dihydroxy (calcitriol), the active form of vitamin D. Vitamin D is important for calcium absorption, bone health, and normal muscle and immune function. The active form is produced through steps in the liver and kidneys, so its level can be useful when a provider is evaluating low calcium, bone disease, or kidney conditions. It may be ordered alongside other vitamin D and calcium tests. Results are interpreted with parathyroid hormone, calcium, phosphate, and kidney function for a complete view.

• Vitamin D 25-dihydroxy (calcitriol) Measures the active form of vitamin D in the blood.
• Calcium Often measured because vitamin D regulates calcium.
• Phosphate Often measured because vitamin D affects phosphate balance.
• Parathyroid hormone (PTH) May be measured to assess how calcium regulation is working.

• People with low calcium or bone-related symptoms
• Individuals with kidney disease being monitored
• People with suspected vitamin D metabolism problems
• Those being evaluated for parathyroid conditions

• No special preparation is usually required.
• Tell the collector about vitamin D or calcium supplements you take.
• Follow any instructions provided for your specific panel.

Abnormal calcitriol levels are interpreted with calcium, phosphate, parathyroid hormone, and kidney function. Low levels may be seen with kidney or parathyroid conditions, while high levels may relate to other causes. A single value rarely tells the whole story. Discuss results with a healthcare provider, who can interpret the pattern and determine what follow-up is needed.

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