Protocol - Vitamin D

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Any methodology that uses the appropriate National Institute of Standards and Technology (NIST) standard reference material and whose use is monitored by participation in the Vitamin D External Quality Assessment Scheme (DEQAS), can be used to quantify vitamin D exposure.

Specific Instructions





All bioassays that follow the guidelines present in the Description of Protocol are equally valid, and the data collected can be compared across studies.

Personnel and Training Required

Personnel and required training will depend on Vitamin D protocol selected.

Equipment Needs

Equipment needed will depend on Vitamin D protocol selected.

Requirement CategoryRequired
Major equipment No
Specialized training No
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration



Infant, Toddler, Child, Adolescent, Adult, Senior, Pregnancy


All ages, but most important for infants and the elderly

Selection Rationale

The PhenX Working Group selected this protocol because two recent systematic evidence-based reviews suggest that serum 25 hydroxy vitamin D is the best biomarker for vitamin D exposure and captures exposure levels from both diet and sunlight.


Chinese, English

Logical Observation Identifiers Names and Codes (LOINC) PhenX - vitamin D protocol 62288-6 LOINC
Human Phenotype Ontology Vitamin D deficiency HP:0100512 HPO
Human Phenotype Ontology Abnormality of viatmin D metabolism HP:0100511 HPO
caDSR Form PhenX PX051101 - Vitamin D 5850321 caDSR Form
Derived Variables


Process and Review

The Expert Review Panel #1 reviewed the measures in the Anthropometrics, Diabetes, Physical Activity and Physical Fitness, and Nutrition and Dietary Supplements domains.

Guidance from the ERP includes:

• No significant changes to measure

Back-compatible: no changes to Data Dictionary

Previous version in Toolkit archive (link)

Protocol Name from Source

Vitamin D External Quality Assessment Scheme (DEQAS)


National Institute of Standards and Technology (NIST)

Vitamin D External Quality Assessment Scheme (DEQAS)

General References


Protocol ID


Export Variables
Variable Name Variable IDVariable DescriptiondbGaP Mapping
PX051101010100 Vitamin D Concentration in ng/L Variable Mapping
Nutrition and Dietary Supplements
Measure Name

Vitamin D

Release Date

October 30, 2009


A measure to assess serum vitamin D.


Vitamin D functions as a hormone and is one of the most important biological regulators of calcium metabolism, in conjunction with parathyroid hormone and calcitonin. The measurement of 25(OH)D (referred to as the vitamin D assay) is becoming increasingly important in managing patients with various disorders of calcium metabolism associated with rickets, neonatal hypocalcemia, pregnancy, nutritional and renal osteodystrophy, hypoparathyroidism, and postmenopausal osteoporosis.


Nutrition and Dietary Supplements, calcitriol, calcium metabolism, Rickets, hypocalcemia, osteodystrophy, hypoparathyroidism, osteoporosis, DEQAS

Measure Protocols
Protocol ID Protocol Name
51101 Vitamin D

Kwok, R. K., et al. (2017) The GuLF STUDY: A Prospective Study of Persons Involved in the Deepwater Horizon Oil Spill Response and Clean-Up. Environ Health Perspect. 2017 April; 125(4): 570-578. doi: 10.1289/EHP715