1,25 Dihydroxy Vitamin D

You should get a 1,25-dihydroxy vitamin D test when your doctor suspects kidney disease, parathyroid disorders, or unexplained high or low blood calcium. It is also ordered to evaluate sarcoidosis, lymphoma, vitamin D-dependent rickets, and abnormal phosphate levels. It is not used for routine vitamin D deficiency screening.

No special preparation is usually needed for a 1,25-dihydroxy vitamin D test, and fasting is generally not required, though some labs may advise it. Inform your doctor about any vitamin D, calcium, or calcitriol supplements, steroids, or other medications you take, as these can affect results. Follow your lab's specific instructions.

No, fasting is generally not required for a 1,25-dihydroxy vitamin D test. You can eat and drink normally before the test. However, some labs may recommend fasting, so follow their instructions. If other tests like calcium, phosphorus, or blood sugar are ordered alongside it, you may need to fast for 8–12 hours.