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Test Code 25HDD 25-Hydroxyvitamin D2 and D3, Serum

Reporting Name

25-Hydroxyvitamin D2 and D3, S

Useful For

Diagnosis of vitamin D deficiency

 

Differential diagnosis of causes of rickets and osteomalacia

 

Monitoring vitamin D replacement therapy

 

Diagnosis of hypervitaminosis D

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
  Frozen  30 days
  Ambient  7 days

Reference Values

TOTAL 25-HYDROXYVITAMIN D2 AND D3 (25-OH-VitD)

<10 ng/mL (severe deficiency)*

10-19 ng/mL (mild to moderate deficiency)**

20-50 ng/mL (optimum levels)***

51-80 ng/mL (increased risk of hypercalciuria)****

>80 ng/mL (toxicity possible)*****

*Could be associated with osteomalacia or rickets

**May be associated with increased risk of osteoporosis or secondary hyperparathyroidism

***Optimum levels in the healthy population; patients with bone disease may benefit from higher levels within this range

****Sustained levels >50 ng/mL 25OH-VitD along with prolonged calcium supplementation may lead to hypercalciuria and decreased renal function

*****80 ng/mL is the lowest reported level associated with toxicity in patients without primary hyperparathyroidism who have normal renal function. Most patients with toxicity have levels >150 ng/mL. Patients with renal failure can have very high 25-OH-VitD levels without any signs of toxicity, as renal conversion to the active hormone 1,25-OH-VitD is impaired or absent.

 

These reference ranges represent clinical decision values, based on the 2011 Institute of Medicine report, that apply to males and females of all ages, rather than population-based reference values. Population reference ranges for 25-OH-VitD vary widely depending on ethnic background, age, geographic location of the studied populations, and the sampling season. Population-based ranges correlate poorly with serum 25-OH-VitD concentrations that are associated with biologically and clinically relevant vitamin D effects and are therefore of limited clinical value.

 

For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Day(s) and Time(s) Performed

Monday through Friday; Continuous until 2:30 p.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82306

LOINC Code Information

Test ID Test Order Name Order LOINC Value
25HDN 25-Hydroxyvitamin D2 and D3, S 49590-3

 

Result ID Test Result Name Result LOINC Value
2897 25-Hydroxy D2 49054-0
2898 25-Hydroxy D3 1989-3
83670 25-Hydroxy D Total 62292-8

Clinical Reference

1. Jones G, Strugnell SA, DeLuca HF: Current understanding of the molecular actions of vitamin D. Physiol Rev 1998 Oct;78(4):1193-1231

2. Miller WL, Portale AA: Genetic causes of rickets. Curr Opin Pediatr 1999 Aug;11(4):333-339

3. Vieth R: Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Am J Clin Nutr 1999 May;69(5):842-856

4. Vieth R, Ladak Y, Walfish PG: Age-related changes in the 25-hydroxyvitamin D versus parathyroid hormone relationship suggest a different reason why older adults require more vitamin D. J Clin Endocrinol Metab 2003 Jan;88(1):185-191

5. Wharton B, Bishop N: Rickets. Lancet 2003 Oct 25;362(9393):1389-1400

6. Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Edited by AC Ross, CL Taylor, AL Yaktine, HB Del Valle. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC. National Academies Press (US), 2011 Available from: www.ncbi.nlm.nih.gov/books/NBK56070

Method Description

Deuterated stable isotope is added as internal standard. 25-Hydroxyvitamin D2 (25-OH-VitD2), 25-hydroxyvitamin D3 (25-OH-VitD3), and the internal standard are extracted. The extracts are then derivatized before being analyzed by liquid chromatography-tandem mass spectrometry using multiple reaction monitoring. 25-OH-VitD2 and 25-OH-VitD3 are quantified and reported individually and as a sum with a clinical reference range attached to the sum. For children under 1 year of age, a modified assay is performed to identify and eliminate interference due to C-3 epimers of 25-OH-VitD2 and 25-OH-VitD3.(Zimmer D, Pickard V, Czembor W, Muller C: Comparison of turbulent-flow chromatography with automated solid-phase extraction in 96-well plates and liquid-liquid extraction used as serum sample preparation techniques for liquid chromatography-tandem mass spectrometry. J Chromatogr A 1999 Aug 27;854[1-2]:23-35)

Analytic Time

2 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Renal Diagnostics Test Request (T830)