Vitamin D 25 (Deficiency)

Alphabetical Test listing

Vitamin D 25 (Deficiency)-113A

Vitamin D 25 (Deficiency)
25-Hydroxyvitamin D2 & D3
D2, D3 VTD
Vitamin D 25 hydroxy (D2 +D3)
  • Diagnosis of Vitamin D deficiency
  • Monitoring vitamin D replacement therapy 
1.0 mL
0.5 mL

Immediately following collection, thoroughly mix sample by gently inverting 5 times

  1. Allow sample to clot for a minimum of 30 minutes
  2. Spin within two (2) hours of sample collection

Gold serum separator (SST) tube


  1. Allow sample to clot
  2. Spin
  3. Transfer serum to a False bottom plasma/serum transport vial/tube (AHL), labelled as serum, within two (2) hours of sample collection

Refrigerated (preferred) - 12 days

Frozen - 1 month

Ambient - 72 hours

  • Improper labels (unlabeled or mislabeled)
  • Hemolysis (some procedures)
  • Improper anticoagulant or ratio
  • Delay in transport
  • Improper storage temperature affecting results
  • Improper container
  • Leaking container resulting in compromised specimen
  • Quantity not sufficient (QNS)
AHL - Chemistry: C
1 day

Chemiluminescent Microparticle Immunoassay (CMIA)


Deficiency:         < 20 ng/mL
Insufficiency:         20-29 ng/mL
Sufficiency:            30-80 ng/mL
Possible Toxicity: > 80 ng/mL

Based on Institute of Medicine recommendations


25-OH Vitamin D plays a key role in the maintenance of mineral balance and skeletal integrity. Long associated only with its role in bone formation; Vitamin D is actually active throughout the human body, influencing immune system responses and cell defenses.

Total Vitamin D is made up of the subunits D2 and D3 and is not really a vitamin since D3 can be synthesized by the skin after sunshine exposure. The main cause of Vitamin D deficiency is lack of sun exposure (with clothing) not compensated by diet. Vitamin D deficiency is a growing health problem because of lack of exposure to sunlight and insufficient dietary intake.

The major dietary sources of Vitamin D3 are oily fish (salmon, mackerel). Vitamin D2 comes from yeasts and plants and has about the same potency as Vitamin D3 in humans. However, the contribution of this metabolite in the diet is very low with the exception of vegetarians. Vitamin D can also be obtained from fish liver oils, foods fortified with Vitamin D, multivitamins and Vitamin D preparations. Fortified food or supplements may contain Vitamin D2 and/or Vitamin D3.