No upper limit for Vitamin D reference interval?
The Oxford Handbook of Clinical Medicine (14th Ed.) provides reference intervals for biochemistry tests and includes the following for Vitamin D:
- <25nmol/ L = deficiency
- 25– 50nmol/ L = insufficiency
- >50nmol/ L = treatment target
Can anyone explain to me why no upper limit is provided here, like most other tests? Does it have something to do with the fact that tolerable daily intakes are quite high and toxicity unlikely/rare?