Discussions that mention phenytoin

Arthritis board

they go by 25-Hydroxy vitamin D test
25-OH Vitamin D test
both are the same.
I think they have to request this specific test and is not on a cbc panel.
cbc meaning: complete blood count.

here is some further information on this vitamin and lack of or too much of.
Why the Test Is Performed

This test is used to determine if a person has a deficiency or excess of vitamin D.

25-hydroxy vitamin D is stored in the liver, where it is converted from other forms of vitamin D. These other forms are either obtained from food or made in the skin by exposure to sunlight. 25-hydroxy vitamin D is changed to its active form, 1,25-dihydroxy vitamin D in the kidney. This active form of vitamin D keeps normal levels of calcium and phosphate in the blood by acting primarily on the intestines, kidneys, and bones.

Low 25-hydroxy vitamin D levels indicate a deficiency in vitamin D. Vitamin D deficiency can result from lack of exposure to sunlight, lack of adequate vitamin D in the diet, liver and kidney diseases, malabsorption, and medications such as phenytoin, phenobarbital, and rifampin. Vitamin D deficiency may lead to low blood calcium levels (hypocalcemia), thin or weak bones (osteoporosis and osteomalacia), and high levels of parathyroid hormone (secondary hyperparathyroidism).

High 25-hydroxy vitamin D indicates excess vitamin D (hypervitaminosis D) and is usually caused by too much vitamin D in the form of doctor-prescribed dietary supplements. This can lead to high calcium levels (hypercalcemia).

hope this is of some help to you.