Diagnosis of Vitamin D Deficiency and Dependency Levels of 25 (OH) D (D2 + D3) Vitamin D deficiency may be suspected based on any of the following: A history of inadequate sunlight exposure or dietary intake Symptoms and signs of rickets, osteomalacia, or neonatal tetany Characteristic bone changes seen on x-ray X-rays of the radius and ulna plus serum levels of calcium, phosphate, alkaline phosphatase, parathyroid hormone (PTH), and 25 (OH) D are needed to differentiate vitamin D deficiency from other causes of bone demineralization.