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Test Code VitD Vitamin D, 25-Hydroxy Level

Important Note

For orders that originate outside of Seattle Children's, this is the default test for Vitamin D assessment, unless "Vitamin D 25-Hydroxy Fractionated" is specifically requested.

Clinical System Name

Vitamin D, 25-Hydroxy Level


Useful in the nutritional assessment for Vitamin D status. This test provides a total Vitamin D measurement (25-OH Vitamin D2 and 25-OH Vitamin D3); if Vitamin D2 is used for supplementation (this is not common), consider ordering Vitamin D 25-Hydroxy Fractionated.

Sample Requirements

Specimen: Whole Blood

Container(s): Gold SST, Red, Gold Microtainer

Preferred Vol: 2 mL

Minimum Vol: 1 mL



Processing Instructions

Reject due to:

Spin: Y

Aliquot: Y

Temp: 2- 8 C

Storage location: Transfer 0.7 mL serum to plastic tube. Deliver to CPA refrigerator, FrigF Rack. 


Off-site collection:  Allow blood to clot for serum; spin blood and refrigerate serum.


Specimen Type Temperature Time
serum Room temp 2 h
  Refrigerated 7 d
  Frozen 1 m


Up to 3 freeze/thaw cycles are acceptable.


STAT Performed TAT
N M-F, Su 1 - 2 d


Performing Laboratory

Seattle Children's Laboratory 


Department:  Chemistry

Location: Chem East

Phone Number: 206-987-2617

Reference Range

Vitamin D sufficiency ≥ 30 ng/mL
Vitamin D insufficiency 15 - 30 ng/mL
Vitamin D deficiency < 15 ng/mL


Note: Cord blood levels tend to be lower (30 - 50%) in the US. Levels of Vitamin D vary with exposure to sunlight, peaking in the summer in ambulatory individuals.


Method: Immunoassay by Bioplex 2200

Analytical Volume: 0.5 mL serum


CPT Codes



25-Hydroxyvitamin D

25-OH Vitamin D



Vitamin D2

Vitamin D3

Vitamin D Level, Nutritional