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Test Code Billings Clinic: 4893 25-OH Vitamin D, Serum

Performing Laboratory

Billings Clinic Laboratory: Chemistry

Useful For

  • Diagnosis of vitamin D deficiency
  • Differential diagnosis of causes of rickets and osteomalacia
  • Monitoring vitamin D replacement therapy
  • Diagnosis of hypervitaminosis D

Methodology

Immunoassay/PMP/Fluorescein

Specimen Requirements

  • Draw blood in a plain, red-top tube(s) or a serum gel tube.
  • Spin down and send 2 mL of serum refrigerated.

Storage/Stability

Specimen Type Temperature Time
Serum Refrigerated(preferred) 7 days
  Frozen 1 month
  Ambient 24 hours

Reject Due To

  • Specimens stored at room temperature > 24 hours
  • Specimens with obvious microbial contamination
  • Specimens frozen and thawed greater than 4 times
  • Specimens that contain fluorescein
  • Hemolysis

Reference Values

30 - 100 ng/mL

 

INTERPRETIVE REMARKS

Deficiency:     <20 ng/mL

Insufficiency:  20 - 30 ng/mL

Sufficiency:    30 - 100 ng/mL

Toxicity:         >100 ng/mL

 

Vitamin D levels may exhibit seasonal variations. Winter values may be 30-50% lower due to reduced sunlight exposure. Population reference ranges can vary widely depending on age, ethnic background, BMI, and geographic location.

 

 

Day(s) Test Set Up

Daily

Test Classification and CPT Coding

82306 - Vitamin D; 25 hydroxy, includes fraction(s), if performed

LOINC Code Information

Reporting Name LOINC Code
25-OH Vitamin D 1989-3