25-hydroxyvitamin D

Alternative names, keywords

Vitamin D, 25-hydroxy vitamin D, 25-OH vitamin D, 25 OHD

Samples required

● 5 mL clotted blood. Smaller tubes are available for paediatric samples.

Avoid haemolysis.

Test indications

For investigation of suspected vitamin D deficiency or toxicity.

For suspected deficiency in adults measurement is only indicated for:

  • Musculoskeletal symptoms that may be due to vitamin D deficiency.
  • Suspected bone disease that may be improved with vitamin D treatment.
  • Known bone disease where correction of vitamin D deficiency is needed prior to specific treatment.

See NICE Clinical Knowledge Summary: Vitamin D deficiency in adults

Test information

Assay detects both D3 (cholecalciferol) and D2 (ergocalciferol) forms.

Restrictions are in place for this test to prevent inappropriate repeat requesting. See minimum requesting intervals for more information and downloadable override form.

Factors affecting test performance/ results

Haemolysis may cause interference - potentially affected results (serum Hb > 2g/L) will be blocked..

Very high dose biotin (>20 mg/day) may interfere - please contact lab if further information required.

In rare cases, interference due to extremely high titres of antibodies to analyte-specific antibodies, streptavidin or ruthenium can occur.

Results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.

Reference range

> 50 nmol/L

Source: local consensus

Turnaround time

One working day*

*analysis not available at weekends.

Enquiries

Biochemistry (Automation)

 

Details