Vitamin D
Biochemistry Overview / Directory
Purpose of the test
Assessment of vitamin D status is relevant in disturbances of calcium homeostasis. As 25-hydroxy vitamin D (25-OH-D) has a relatively long half-life and is the most abundant form of vitamin D, it is most often measured to assess vitamin D status. Its measurement is indicated in cases of suspected vitamin D deficiency e.g. rickets (children), osteomalacia (adults), neonatal hypocalcaemia, nutritional osteodystrophy (especially in the elderly, institutionalised and Asian populations, malabsorption (e.g. in cystic fibrosis, primary biliary cirrhosis) and in patients on long-term anticonvulsant therapy (barbiturate and phenytoin combination therapy in particular). Cases of vitamin D toxicity are rare and almost always iatrogenic in nature. In renal failure conversion of 25-OH-D to 1,25-OH-D may be inadequate, in which case measurement of calcitriol may be required.
Sample Requirements
Serum (100 µL) is required.
Storage and Transport
Stable at 4°C for up to three days. Send by overnight first class post.
Turnaround Time
One to two weeks.
Price
Price available on application - please contact adrianturner1@nhs.net. Discounts could be available for significant workloads.
Contacts
Ms Tracy Dew
T 020 3299 4134
Miss Rachel Langworthy
T 020 3299 4130
References
Dhesi JK, Bearne LM, Moniz C, Hurley MV, Jackson SH, Swift CG, Allain TJ. (2002) Neuromuscular and psychomotor function in elderly subjects who fall and the relationship with vitamin D status. J Bone Miner Res 17: 891-7.
Dhesi JK, Moniz C, Close JC, Jackson SH, Allain TJ. (2002) A rationale for Vitamin D prescribing in a falls clinic population. Age Aging 31: 267-71
