Vitamin D, 1,25-Dihydroxy Blood Test

Active Vitamin D Blood Test for Calcitriol, Calcium, Kidney & Parathyroid Evaluation

The Vitamin D, 1,25-Dihydroxy Blood Test measures the active form of vitamin D in the blood, also known as calcitriol.

This test may be used when a healthcare provider wants to evaluate active vitamin D metabolism, calcium-related concerns, kidney function-related vitamin D processing, or certain parathyroid-related conditions.

✔ Measures active vitamin D, also called calcitriol
✔ May be used for calcium, kidney, or parathyroid-related evaluation
✔ Not the usual test for routine vitamin D deficiency screening
✔ Doctor's order included
✔ No insurance required

What This Test Measures

Vitamin D, 1,25-Dihydroxy

This blood test measures 1,25-dihydroxyvitamin D, the active hormone form of vitamin D. Vitamin D is first converted in the liver to 25-hydroxyvitamin D and then converted mainly in the kidneys to 1,25-dihydroxyvitamin D.

• Test name: Vitamin D, 1,25-Dihydroxy
• Also known as: Calcitriol, 1,25-Dihydroxy Vitamin D, 1,25 di-OH Vitamin D
• Sample type: Blood
• Common result unit: pg/mL
• Estimated result time: Typically about 2 to 4 business days, but timing may vary

Important: This Is Not the Standard Vitamin D Deficiency Test

The Vitamin D, 1,25-Dihydroxy test is not usually the best test for routine vitamin D deficiency screening.

If you are trying to check general vitamin D status or vitamin D deficiency, the more commonly used test is usually Vitamin D, 25-Hydroxy.

A person may have a normal Vitamin D, 1,25-Dihydroxy result even when overall vitamin D stores are low. If you are unsure which vitamin D test you need, confirm with your healthcare provider before ordering.

Why Order a Vitamin D, 1,25-Dihydroxy Test?

• Calcium metabolism evaluation - May be ordered when calcium levels are abnormal.
• Parathyroid-related evaluation - May help support evaluation of parathyroid function concerns.
• Kidney-related evaluation - May be used when kidney function affects vitamin D activation.
• Renal osteodystrophy monitoring - May be used in certain kidney-related bone health evaluations.
• Provider-directed testing - Useful when a healthcare provider specifically requests active vitamin D testing.

Who May Need This Test?

This test may be appropriate for:

• Individuals whose provider requested Vitamin D, 1,25-Dihydroxy testing
• Patients being evaluated for certain calcium abnormalities
• Patients being evaluated for parathyroid-related concerns
• Individuals with kidney-related vitamin D metabolism concerns
• Patients being monitored for specific bone or mineral metabolism disorders

Vitamin D 1,25-Dihydroxy vs Vitamin D 25-Hydroxy

These two vitamin D tests are different and are used for different purposes.

• Vitamin D, 25-Hydroxy - Commonly used to check overall vitamin D status and vitamin D deficiency.
• Vitamin D, 1,25-Dihydroxy - Measures the active form of vitamin D and is more often used for calcium, kidney, or parathyroid-related evaluation.

If your goal is routine vitamin D deficiency screening, consider whether the Vitamin D, 25-Hydroxy test is the correct option for your needs.

Important Information Before Testing

• This test measures active vitamin D only.
• This test does not replace the Vitamin D, 25-Hydroxy test for routine deficiency screening.
• This test does not diagnose kidney disease, parathyroid disease, sarcoidosis, lymphoma, or any medical condition by itself.
• Results should be interpreted by a licensed healthcare provider along with your symptoms, calcium levels, kidney function, and other lab results.
• Result timing is an estimate and may vary due to lab processing, holidays, weather, repeat testing, or other delays.

How It Works

1. Order online.
2. Receive your lab order. A doctor's order is included.
3. Visit a participating lab location.
4. Complete a simple blood draw.
5. Receive your results. Results are typically available in a few business days, but timing may vary.

Why Choose This Test?

✅ Measures active vitamin D, also called calcitriol
✅ Useful when specifically requested by a healthcare provider
✅ May support calcium, kidney, or parathyroid-related evaluation
✅ Doctor's order included
✅ No insurance needed
✅ Convenient online ordering

Frequently Asked Questions

What does the Vitamin D, 1,25-Dihydroxy test check?

This test checks the active form of vitamin D in the blood, also called calcitriol.

Is this the same as a regular vitamin D test?

No. The regular vitamin D test used for most deficiency screening is usually Vitamin D, 25-Hydroxy. This test measures Vitamin D, 1,25-Dihydroxy, which is the active form of vitamin D.

Should I order this for vitamin D deficiency?

Usually, Vitamin D, 25-Hydroxy is the more common test for vitamin D deficiency screening. Order this test if your healthcare provider specifically requested Vitamin D, 1,25-Dihydroxy.

Do I need to fast?

Fasting is usually not required unless your healthcare provider gives you different instructions.

How long do results take?

Results are typically available in about 2 to 4 business days, but timing may vary by lab, location, holidays, weather, or additional processing.

Is a doctor's order included?

Yes. A doctor's order is included with this lab test.

Does this test diagnose a medical condition?

No. This test provides a lab value and should be reviewed with your healthcare provider along with your medical history and any other test results.

Order Your Vitamin D, 1,25-Dihydroxy Blood Test

Use this test when you need active vitamin D testing for provider-directed evaluation of calcitriol, calcium metabolism, kidney-related concerns, parathyroid-related concerns, or other specific medical review.

Order your Vitamin D, 1,25-Dihydroxy Blood Test today.