25-Hydroxy Vitamin D, Serum

What it is:
This test measures the main circulating form of vitamin D (25-hydroxy vitamin D) in the blood. It reflects overall vitamin D status in the body.

Uses

• Diagnose vitamin D deficiency or excess

• Evaluate causes of bone disorders: rickets, osteomalacia, osteoporosis

• Monitor effectiveness of vitamin D supplementation

Symptoms That May Lead to the Test

• Bone pain or tenderness

• Frequent fractures

• Muscle weakness

• Fatigue

• Growth abnormalities in children

Abnormal Results

• Low levels:

  • Vitamin D deficiency

  • Malabsorption disorders

  • Kidney or liver disease

  • Inadequate sunlight exposure

• High levels:

  • Excessive supplementation

  • Sarcoidosis

  • Certain lymphomas

Risks

• Minimal, limited to standard risks of a blood draw (mild pain, bruising, or dizziness).