• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

This test is used to determine if a patient has a deficiency or excess of vitamin D.
25-hydroxy vitamin D is the most accurate measure of vitamin D stores in the body.

25-hydroxy vitamin D is stored in the liver where it is converted from other forms of vitamin D either obtained from the diet or made in the skin by sunlight. 25-hydroxy vitamin D is then changed to its active form, 1,25-dihydroxy vitamin D in the kidney. This active form of vitamin D causes increases in calcium and phosphate by activity primarily on the intestines, kidney and bone.

Low 25-hydroxy vitamin D levels indicate a deficiency in vitamin D, either from lack of exposure to sunlight or lack of adequate vitamin D in the diet. 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).

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins