Vitamin D (Blood)

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Auckland Te Toka Tumai

Test Guide

Vitamin D (Blood)

Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Chemical Pathology

Delphic Registration Code (Alpha Code)

D25

Test Code (Numeric Code)

3746

Laboratory Handling

Phlebotomy

LabPLUS DOES NOT accept patient payment for Vitamin D testing. The only exception to this is non-residents where all tests are paid for.

Laboratory

SCP - Endrocrinology

Sample Stability

Stable for 5 days at 4oC. Freeze if arrival at LabPlus will be longer

Synonyms

25-hydroxycholecalciferol, 25-hydroxyvitamin D, Cholecalciferol , D25 , Vitamin D

Turnaround Time

1 week

Performed Weekly

This test may be vetted by the laboratory. Please include relevant clinical information on the request form to ensure appropriate tests are approved. See the 'Clinical Information' section below for more information on the indications for testing.

Specimen Type

Serum

Specimen Requirements

Tube/Container Type:

Preferred

SST II (Gold Cap)

Acceptable

Plain (Red Top)

Preferred Sample Volume (ml)

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

Plain(Microtainer)

Preferred Sample Volume (ml)

0.5

Pre-testing Requirements

This test is currently restricted and only available for patients <16 years of age. Any other clinically urgent request should be referred to a Chemical Pathologist. Declined tests: If a test is declined, the specimen will be held for a reasonable period (usually 3 weeks but dependant on the stability of the sample). Medical practitioners seeking approval for a declined test should email the on-call Chemical Pathologist (chemicalpathologist@adhb.govt.nz ), giving the patient's name and NHI number and the clinical justification for the test. If unable to email, call the on-call Chemical Pathologist via Lablink (09-3078995) and identify yourself as a doctor.

Additional Specimen Information

Stability:
Stable for 5 days at 4oC
Freeze if arrival at LabPlus will be longer

This test may require Chemical Pathologist approval.

Diagnostic Use

Vitamin D toxicity

Vitamin D intoxication may occur at levels above 250 nmol/L.

Vitamin D deficiency

Most people with low vitamin D are asymptomatic. If prolonged and severe, vitamin D deficiency may lead to rickets in children and osteomalacia in adults; these are uncommon conditions. The role of low vitamin D as a contributing factor to osteoporosis is still a matter of debate. Overall evidence from RCT’s suggests that supplementation with vitamin D does not have consistent benefits for fracture prevention (3,8). It is not necessary to routinely measure vitamin D in patients with low bone density.

Individuals who are at risk of symptomatic vitamin D deficiency are those of Indian or African descent, frail institutionalized elderly, and those who avoid sunlight for cultural or medical reasons. In such individuals, vitamin D supplementation is reasonable without blood testing. There is insufficient evidence to support routine vitamin D supplementation or testing vitamin D levels in healthy community-dwelling individuals.

Pregnancy: Available evidence does not suggest that pregnant women are at increased risk of vitamin D deficiency compared with the nonpregnant population (7). Current guidelines do not support routine testing of vitamin D levels in pregnancy (6)

Labplus Policy on vitamin D testing

Due to staffing restrictions, not all vitamin D tests can be performed. They will be automatically declined if the patient is 16 years or older. Testing may be performed with pathologist approval (see list below). In the vast majority of cases, requests were nor indicated. The current approach to patients at risk of deficiency is to simply supplement.

The test will be performed only when:

Ordered by the following specialists: endocrinologist, gastroenterologist, bariatric surgeon, rheumatologists and nephrologists
Ordered for specific high risk groups for rickets/osteomalacia (e.g. cystic fibrosis, proven malabsorption, bariatric surgery, refugees, deeply pigmented skin, full veil wearers)
Ordered for the investigation of rickets/osteomalacia, disorders of calcium and phosphate metabolism, or osteoporosis
All requests on children (less than 16 y ) will be approved.
Ordered for other patients after discussion with, and approval by, a Labplus Chemical Pathologist

The indication (reason) for the test must be stated on the request form (e.g. “hypocalcemia” or “cystic fibrosis”)

Labtests (a private community laboratory) are able to perform the vitamin D test if the patient wishes to pay for it. A separate request form is required and must contain the words ‘patient to pay’. If you require this test performed by Labplus (Auckland Hospital) at public expense, please search “pathologist” in this Test Guide for the procedure for obtaining pathologist approval.

Reference Intervals

Units: nmol/L

Reference interval:

< 25	Moderate to severe vitamin D deficiency
25 – 50	Mild vitamin D deficiency
50- 150	Optimal target range for bone health
> 250	Vitamin D intoxication has been reported above this level, but is rare at levels < 500 nmol/L.

Conversion factor : ng/mL x 2.5 = nmol/L

Test Method

Principle : Direct competitive chemiluminescence
Assay : 25OH Vitamin D Total
Analyser : Diasorin Liaison XL

Uncertainty of Measurement

12%

Last updated: 19/08/2026

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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 #

Testing Laboratory

Department

Delphic Registration Code (Alpha Code)

Test Code (Numeric Code)

Laboratory Handling

Phlebotomy

Laboratory

Sample Stability

Synonyms

Turnaround Time

Specimen Type

Specimen Requirements

Tube/Container Type:

Preferred

Acceptable

Preferred Sample Volume (ml)

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

Preferred Sample Volume (ml)

Pre-testing Requirements

Additional Specimen Information

Diagnostic Use

Vitamin D toxicity

Vitamin D deficiency

Labplus Policy on vitamin D testing

Reference Intervals

Test Method

Uncertainty of Measurement

Contact Information

Enquiry Form

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Vitamin D (Blood)

Overview

Testing Laboratory

Department

Delphic Registration Code (Alpha Code)

Test Code (Numeric Code)

Laboratory Handling

Phlebotomy

Laboratory

Sample Stability

Synonyms

Turnaround Time

Specimen

Specimen Type

Specimen Requirements

Tube/Container Type:

Preferred

Acceptable

Preferred Sample Volume (ml)

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

Preferred Sample Volume (ml)

Pre-testing Requirements

Additional Specimen Information

Referral

Clinical Information/Test Method

Diagnostic Use

Vitamin D toxicity

Vitamin D deficiency

Labplus Policy on vitamin D testing

Reference Intervals

Test Method

Uncertainty of Measurement

Additional Information

Contact Information

Contact Information

Enquiry Form

Search tests