CBC (Complete Blood Count)

The a blood test that measures the level of 25-hydroxy vitamin D in the body, which is the main form of vitamin D circulating in the blood. This vitamin is essential for healthy bones, teeth, muscles, and immune function because it helps the body absorb calcium and phosphorus.

Doctors usually recommend this test if a person has symptoms like bone pain, muscle weakness, frequent fractures, or fatigue, or if there is a risk of deficiency due to low sun exposure, poor diet, older age, or certain medical conditions.

Low levels of vitamin D3 may lead to rickets in children, osteoporosis or osteomalacia in adults, weak immunity, and higher risk of chronic diseases. High levels (from excess supplements) can also cause health problems, so the test helps in balancing the right amount.