The 25-hydroxy vitamin D test measures the amount of 25-hydroxy vitamin D in blood serum. 25-hydroxy vitamin D is the most accurate measure of vitamin D stores in the body. This essential nutrient is actually a precursor hormone — the building block of a powerful steroid hormone in your body called calcitriol. It’s been known for many years that vitamin D is critical to the health of our bones and teeth, but our deeper insight into D’s true role in our health is quite new.
Why Vitamin D?
Vitamin D works in connection with other nutrients and hormones in your body to support healthy bone renewal — the ongoing process of mineralization and demineralization that when out of control shows up as rickets in children and osteomalacia (“soft bones”) in adults.
Researchers are discovering that D also promotes normal cell growth and differentiation throughout the body, a key factor in maintaining hormonal balance and a healthy immune system. It appears that calcitriol actually becomes part of the physical composition of cells, assisting in the buildup and breakdown of healthy tissue — in other words the process that keeps you well. Vitamin D has even been implicated in the prevention of cancer.
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.
The Test
It is a blood test, when the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing but you can return to your day-to-day activities afterwards.
The recommended range is 30 to 100 ng/mL. Recommended ranges may vary slightly among different laboratories. The Optimal range is 45-50 ng/mL, with some doctors recommending levels as high as 75 ng/mL. Vitamin D deficiency may be characterized by:
- Muscle pain
- Weak bones/fractures
- Low energy and fatigue
- Lowered immunity
- Depression
- Mood swings
- Sleep irregularities
Women with renal problems or intestinal concerns (such as Irritable Bowel Syndrome or Crohn’s disease) may be vitamin D deficient because they can neither absorb nor adequately convert this nutrient.
Visit www.vitaminDcouncil.org for additional information on Vitamin D or contact us for more information and set up an appointment.
