Vitamin D, 25-Hydroxy
| Order Code: | VITD25 |
| Order Form: | Laboratory Requisition |
Specimen:
Plasma
Collection Medium:
 |
| Plasma Separator Tube |
Minimum:
3 mL whole blood from light green top tube or TWO microtainers for
pediatric patients.
Analytic Time:
2 hours (upon receipt in laboratory)
Reference Range:
Reference range in Epic: 20-80 ng/mL
Deficiency: Less than 20 ng/mL
Borderline: 20-29 ng/mL
Optimum level: 30-80 ng/mL
Possible toxicity: > 150 ng/mL
Deficiency: Less than 20 ng/mL
Borderline: 20-29 ng/mL
Optimum level: 30-80 ng/mL
Possible toxicity: > 150 ng/mL
Interpretive Data:
This is the appropriate screening test for routine assessment of
vitamin D nutritional status. This assay accurately quantifies the sum of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2. 25-Hydroxyvitamin D reference ranges are a controversial topic, with some authorities suggesting optimal concentrations should be 30 ng/mL or higher based on correlations of 25-hydroxyvitamin D plasma concentrations with physiological parameters such as parathyroid hormone or calcium concentrations.
Institute of Medicine (IOM) and World Health Organization (WHO) guidelines designate 25-hydroxyvitamin D plasma concentrations below 20 ng/mL as deficient, based on increased frequency of adverse outcomes (e.g., osteoporotic fractures). However, optimal 25-hydroxyvitamin D concentrations greater than 20 ng/mL may be considered for specific disease conditions. 25-Hydroxyvitamin D concentrations should be interpreted in context of clinical history and physical examination along with other laboratory studies, if indicated. For workup of hypercalcemia, vitamin D status in renal failure patients, and certain malignancies, "Vitamin D (1,25-dihydroxy)" may be indicated.
vitamin D nutritional status. This assay accurately quantifies the sum of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2. 25-Hydroxyvitamin D reference ranges are a controversial topic, with some authorities suggesting optimal concentrations should be 30 ng/mL or higher based on correlations of 25-hydroxyvitamin D plasma concentrations with physiological parameters such as parathyroid hormone or calcium concentrations.
Institute of Medicine (IOM) and World Health Organization (WHO) guidelines designate 25-hydroxyvitamin D plasma concentrations below 20 ng/mL as deficient, based on increased frequency of adverse outcomes (e.g., osteoporotic fractures). However, optimal 25-hydroxyvitamin D concentrations greater than 20 ng/mL may be considered for specific disease conditions. 25-Hydroxyvitamin D concentrations should be interpreted in context of clinical history and physical examination along with other laboratory studies, if indicated. For workup of hypercalcemia, vitamin D status in renal failure patients, and certain malignancies, "Vitamin D (1,25-dihydroxy)" may be indicated.
Comments:
References
Holick MF, NEJM 357: 266-281, 2007.
Krasowski MD, Am J Clin Pathol 136: 507-514, 2011.
Vieth R. Am J Clin Nutr 69:842-856, 1999.
Vieth R, Ladak Y, Walfish PG. J Clin Endocrinol Metab 88:185-191, 2003.
Wharton B, Bishop N. Lancet 362:1389-1400, 2003.
Holick MF, NEJM 357: 266-281, 2007.
Krasowski MD, Am J Clin Pathol 136: 507-514, 2011.
Vieth R. Am J Clin Nutr 69:842-856, 1999.
Vieth R, Ladak Y, Walfish PG. J Clin Endocrinol Metab 88:185-191, 2003.
Wharton B, Bishop N. Lancet 362:1389-1400, 2003.
Methodology:
Chemiluminescent microparticle immunoassay (CMIA)
Instructions:
Contact University of Iowa Diagnostic Laboratories
1-866-844-2522 (toll free)
319-384-7213 (Fax)
1-866-844-2522 (toll free)
319-384-7213 (Fax)
CPT Code:
82306