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Test Code VITD Vitamin D, 25-OH, Total

Additional Codes

Epic: LAB8614

Specimen Required

Specimen Type: Serum

Collection Container/Type

Preferred: Serum gel

Acceptable: Green top (Lithium heparin)

Submission Container/Tube: Plastic 

Specimen Volume: 3 mL

Collection Instructions: Centrifuge and separate cells after clot formation and within 4 hours of collection. 

Specimen Minimum Volume

0.2 mL

Specimen Stability

Room temperature: 3 days

Refrigerated (on gel): 3 days

Refrigerated (off gel): 12 days

Frozen: 3 months

Reference Range

<20 ng/mL (deficiency)

20 - 30 ng/mL (insufficiency)

≥ 30 ng/mL (Optimal)


Vitamin D, 25-OH, Total: Testing performed using ABBOTT Architect chemiluminescent microparticle immunoassay methodology. Method-dependent minor difference may exist based on the test platform used.

Rejection Due To

Unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.

Report Available

Same day

Clinical Significance

Vitamin D is a fat-soluble steroid prohormone mainly produced photochemically in the skin from 7-dehydrocholesterol.

Two forms of vitamin D are biologically relevant – Vitamin D3 (Cholecalciferol) and Vitamin D2 (Ergocalciferol). Both Vitamins D3 and D2 can be absorbed from food, with Vitamin D2 being an artificial source, but only an estimated 10-20% of vitamin D is supplied through nutritional intake. Vitamins D2 and D3 can be found in vitamin supplements. Vitamin D is converted to the active hormone 1,25-(OH)2-vitamin D(calcitriol) through two hydroxylation reactions. The first reaction occurs in the liver, converting Vitamin D into 25-OH vitamin D. The second reaction, occurring in the kidneys, converts 25-OH vitamin D into the biologically active 1,25(OH)2-vitamin D. The major storage form of vitamin D is 25-OH vitamin D(half-life of 2-3 weeks) and is present in the blood at up to 1,000 fold higher concentration compared to the active 1,25(OH)2-vitamin (half-life of 4 hours).This assay measures 25-OH Vitamin D.

Measurement of Vitamin D status provides opportunities for preventive and therapeutic interventions for Vitamin D insufficiencies and deficiencies.

Vitamin D deficiency is a cause of secondary hyperparathyroidism, rickets, osteoporosis, osteomalacia. Reduced 25-OH vitamin D concentrations in blood have been associated with an increasing risk of chronic diseases, including common cancers, autoimmune or infectious diseases or cardiovascular problems.

Method Name

Chemiluminescent microparticle immunoassay (CMIA)


25-Hydroxy D2
25-Hydroxy D3
25-Hydroxy Vitamin D
25-OH Vitamin D

Day(s) Performed