The 25-hydroxyvitamin D, 25(OH)D, test accurately reflects the concentration of vitamin D. Vitamin D is composed of vitamin D2 and vitamin D3. Individual testing for vitamin D2 and D3 may be useful as follow-up testing in individuals who do not respond to therapeutic vitamin D supplementation.
The HSE sets a budget for diagnostic tests, ordered by GP's, under the Public Spending Code (PSC). Testing for Vitamin D deficiency is only recommended when a patient presents with clinical indications such as osteoporosis, rickets, malabsorption, raised PTH, H/L Phosphate, Pagets etc. Otherwise, the HSE recommend supplementation of Vitamin D from October to May when the sun is not strong enough in Ireland to make Vitamin D.
Patients may wish to pay for a private Vitamin D test with their GP.