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3epi25ohd2serplmcnc

Published: August 9, 2026Updated: August 14, 2026

This test measures a specific form of vitamin D2 called 3-epi-25-hydroxyvitamin D2 in your blood to help assess your vitamin D status.

Quick summary

{"Measures a specific epimer form of vitamin D2 in your blood","Helps doctors distinguish between different vitamin D supplements and your body's natural vitamin D","Provides more accurate vitamin D status assessment when vitamin D2 supplementation is used","Requires a simple blood draw from a vein in your arm","Results help guide vitamin D supplementation decisions"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 14, 2026Editorial policy

Key facts at a glance

LOINC
72404-7
Short code
3-EPI-25-OH-D2
Synonyms
3-epi-25(OH)D2 SerPl-mCnc
Category
chemistry
Sample
serum
Container
Serum separator tube (SST/Gold top) or plain red top tube
Units
N/A
Ref low
20
Ref high
29
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
CPT
82306
SNOMED
271542005
Specimen volume
1.0 mL minimum serum (2.0 mL preferred for accurate testing)
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Protect from light exposure.
Hemolysis max
50
Lipemia max
300
Icterus max
20
TAT
48–168 hours
Order
routine

What is this test?

The 3-epi-25-hydroxyvitamin D2 test measures the amount of a specific form of vitamin D2 called 3-epi-25-hydroxyvitamin D2 in your serum (blood). Vitamin D2 (ergocalciferol) comes from plant-based sources and supplements, while vitamin D3 (cholecalciferol) comes from sunlight exposure and animal-based foods. When your body processes vitamin D2, it creates various metabolites, and 3-epi-25-hydroxyvitamin D2 is one of these specific forms.

Why is this test ordered?

Your healthcare provider may order this test to: (1) get a more accurate picture of your vitamin D status, especially if you are taking vitamin D2 supplements; (2) distinguish between vitamin D2 and vitamin D3 in your system; (3) monitor vitamin D supplementation effectiveness; and (4) research or investigate specific vitamin D metabolism issues.

How is the test performed?

A healthcare professional will draw a small sample of blood from a vein in your arm using a needle. The blood sample will be sent to a laboratory for analysis. You do not need to fast before this test, but follow any specific instructions from your healthcare provider.

Understanding your results

Your test results will show the concentration of 3-epi-25-hydroxyvitamin D2 in your blood. Your healthcare provider will interpret these results along with other vitamin D tests (like total 25-hydroxyvitamin D) to assess your overall vitamin D status. The presence and amount of the 3-epi form can indicate whether vitamin D2 supplements are being used and how your body is metabolizing them.

Reference range

Reference ranges are laboratory-specific. For 25-hydroxyvitamin D2 (including 3-epi metabolite), optimal levels typically ≥30 ng/mL (75 nmol/L). Insufficient: 20-29 ng/mL. Deficient: <20 ng/mL. Toxicity may be considered >150 ng/mL.N/A

Specimen: serum

No special preparation required. Fasting is not necessary. Maintain standard dietary habits unless otherwise instructed by healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Do I need to fast before this test?
Typically, no fasting is required for this test. However, always follow the specific instructions provided by your healthcare provider or testing facility.
What does it mean if my 3-epi-25-hydroxyvitamin D2 is high?
Elevated levels of 3-epi-25-hydroxyvitamin D2 usually indicate that you are taking vitamin D2 (ergocalciferol) supplements. Your healthcare provider will interpret this in the context of your overall vitamin D status and treatment plan.
Is this different from a regular vitamin D test?
Yes. A regular vitamin D test usually measures total 25-hydroxyvitamin D (both D2 and D3 forms combined). This specific test measures only the 3-epi form of 25-hydroxyvitamin D2, providing more detailed information about vitamin D2 metabolism.
Why would my doctor order this specific test instead of a regular vitamin D test?
Your doctor may order this test if they need to: verify that you are taking vitamin D2 supplements as prescribed; get a more precise measurement of your vitamin D status; or conduct research on your vitamin D metabolism. It provides additional information beyond standard vitamin D testing.
Are there any risks with this blood test?
The risks are minimal and similar to any standard blood draw, including slight bruising, bleeding, or rarely, infection at the puncture site. The procedure is generally very safe.
  1. 1
    LOINC Code 72404-7 ReferenceSource
  2. 2
    Vitamin D Overview - MedlinePlusSource
  3. 3
    Vitamin D and Calcium - National Institutes of Health Office of Dietary SupplementsSource

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 14, 2026. · Read our editorial policy