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Calcitriol (1,25-Dihydroxyvitamin D₃) Serum Mass Concentration

Published: August 9, 2026Updated: August 15, 2026

This test measures the active form of vitamin D in your blood, which plays a key role in calcium metabolism and bone health.

Quick summary

["Active vitamin D helps regulate calcium and phosphate levels, supporting bone strength and overall mineral balance in your body."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
50470-4
Short code
CALC2
Synonyms
Calcit sp2 SerPl-mCnc
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube; plasma may be collected in EDTA or heparin tubes depending on laboratory requirements
Units
N/A
Ref low
0
Ref high
11.5
Critical range
— – 100 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–99 years
Method
Chemiluminescent Immunoassay (CLIA) or Electrochemiluminescent Immunoassay (ECLIA)
CPT
82308
SNOMED
39539002
Specimen volume
1.0 mL serum or plasma; minimum 0.5 mL
Stability
Refrigerated (2-8°C): 24 hours; Frozen (-20°C or below): up to 6 months. For long-term storage, freeze at -70°C. Avoid repeated freeze-thaw cycles.
Hemolysis max
100
Lipemia max
300
Icterus max
25
TAT
24–72 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like bone pain, frequent fractures, or conditions linked to low vitamin D levels, such as osteoporosis or rickets. It may also be used to monitor vitamin D treatment or diagnose vitamin D deficiency or overactivity.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your test is part of a broader metabolic panel. Bring any medications or supplements you’re taking, as they can affect results.

What the Test Involves

A healthcare professional will draw blood from a vein in your arm. The sample is sent to a lab for analysis to measure the precise amount of active vitamin D in your serum.

What the Results Mean

Results help determine if your body is producing enough active vitamin D to maintain healthy calcium levels. Low levels may indicate deficiency, while very high levels could signal overproduction or certain metabolic disorders.

Reference range

Adult males: <11.5 pg/mL; Adult females: <4.6 pg/mL. Reference ranges vary by laboratory methodology and may differ between assays. Pediatric reference ranges differ significantly from adult values.N/A

Specimen: serum

Fasting is not required, though some clinicians prefer a fasting specimen to minimize lipemic interference. Patients should be advised that certain medications including proton pump inhibitors, beta-blockers, and calcium infusion may affect results. For stimulation testing (calcium or pentagastrin), specific protocols should be followed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal levels of active vitamin D can affect bone health, calcium metabolism, and even immune function. Low levels are common in people with limited sun exposure, malabsorption disorders, or chronic kidney disease. High levels may suggest hypercalcemia or vitamin D toxicity, requiring medical evaluation.

Short name

Vitamin D Active Form

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing schedule. Follow-up with your healthcare provider to discuss findings and next steps.
Can vitamin D supplements affect this test?
Yes, vitamin D supplements or certain medications (like calcium or antacids) can influence results. Always inform your provider about all medications or supplements you take before testing.
What symptoms might indicate a need for this test?
Symptoms like persistent bone or muscle pain, frequent fractures, or unexplained fatigue could signal vitamin D imbalance. Your provider may also order it if you have a history of kidney disease, malabsorption issues, or unexplained bone abnormalities.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy