Quick Facts
- Sample: Blood
- Fasting: No special preparation required.
- Turnaround: 3-4 days. May take longer based on weather, holiday, or lab delays.
What This Test Measures
This test measures 1,25 dihydroxyvitamin D, also known as calcitriol, the active form of vitamin D in your blood. Calcitriol is produced in the liver and kidneys from vitamin D 25-hydroxy and plays a role in calcium regulation.
Depending on the lab, this test may report a total calcitriol value, or it may report the individual Vitamin D2 and Vitamin D3 1,25 (OH)2 fractions along with a total. LabCorp reports Calcitriol (1,25 di-OH Vit D) only, while other labs report Vitamin D, 1,25 (OH)2 Total, Vitamin D3, 1,25 (OH)2, and Vitamin D2, 1,25 (OH)2. This test measures the active hormone form of vitamin D, not the storage form, and it is not intended to assess overall vitamin D status.
Benefits
- Measures active calcitriol levels in the blood
- Supports evaluation of hypocalcemia and its possible causes
- Helps monitor bone disease or chronic kidney failure
- Reflects active vitamin D metabolism, not overall vitamin D status
- Reports lab specific fractions when available
Who Is This Test For?
- Individuals being evaluated for hypocalcemia
- People being monitored for bone disease
- Individuals with chronic kidney failure being monitored
- People being evaluated for parathyroid disorders
- Individuals being assessed for suspected renal osteodystrophy
- People being evaluated for vitamin D resistant rickets
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this test?
This test measures 1,25 dihydroxyvitamin D (calcitriol), the active form of vitamin D circulating in your blood. It may help a healthcare provider evaluate hypocalcemia and monitor conditions such as bone disease or chronic kidney failure. This test measures an active hormone level, not a storage marker, and it does not by itself diagnose any condition.
2. Who would benefit from this test?
This test may benefit individuals being evaluated for hypocalcemia or monitored for bone disease, chronic kidney failure, or parathyroid disorders. It may also support evaluation related to renal osteodystrophy or vitamin D resistant rickets. It is not intended for general vitamin D deficiency screening.
3. When should I order this test?
You may consider this test if a healthcare provider is evaluating hypocalcemia, monitoring bone disease, or following chronic kidney failure or parathyroid function. This test measures active calcitriol only and does not replace broader medical or nutritional evaluation.
4. How does this test differ from other nutritional tests?
This test measures the active hormone form of vitamin D, calcitriol, in blood. It differs from the Vitamin D 25-Hydroxy test, which reflects overall vitamin D status and is the recommended test for assessing deficiency or monitoring supplementation. Calcitriol results can appear normal even when overall vitamin D status is deficient, so the two tests are not interchangeable.
5. Do I need to fast before this test?
No special preparation is required for this test.
6. How quickly will I get results?
Results are typically available in 3-4 days. Results may take longer based on weather, holiday, or lab delays.
7. How do I interpret the results?
The meaning of your calcitriol result depends on your symptoms, medical history, kidney function, parathyroid status, and other laboratory findings. A low result may relate to early kidney disease or hypoparathyroidism, while a high result may relate to conditions such as sarcoidosis, certain lymphomas, malignancies, or hyperparathyroidism, but this test alone does not confirm any of these conditions. Results are best interpreted alongside related laboratory findings and a healthcare provider's clinical assessment.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
8. What should I do if my results are abnormal?
If your results fall outside the expected range, review them with a qualified healthcare provider. Additional evaluation or testing may be considered if your provider determines it is appropriate. This test result alone does not provide a complete clinical conclusion.
9. How often should I get tested?
Testing frequency should be determined as directed by your healthcare provider based on your individual health status and monitoring needs.
Pre test preparation
No special preparation required.
