| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Vitamin D, 25-OH, Total
Test CodeVITD
Alias/See Also
Epic: LAB8614
25-Hydroxy D2
25-Hydroxy D3
25-Hydroxy Vitamin D
25-Hydroxycholecalciferol
25-Hydroxyergocalciferol
25-OH Vitamin D
25-Hydroxy D2
25-Hydroxy D3
25-Hydroxy Vitamin D
25-Hydroxycholecalciferol
25-Hydroxyergocalciferol
25-OH Vitamin D
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL
Minimum Volume
0.2 mL
Other Acceptable Specimens
Specimen Type: Plasma
Collection Container: Green top (Lithium heparin)
Instructions
Centrifuge and separate cells after clot formation and within 4 hours of collection.
Transport Container
Plastic vial
Specimen Stability
Room temperature: 3 days
Refrigerated (on gel): 3 days
Refrigerated (off gel): 12 days
Frozen: 3 months
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.
Methodology
Chemiluminescent microparticle immunoassay (CMIA)
Setup Schedule
Daily
Report Available
Same day
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.
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.
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.
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.
Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031
Last Updated: April 17, 2023
Last Review: N. Wolford, April 17, 2023