Vitamin D - Diagnosis Measure: 25 hydroxy-vitamin D 25-OH-D Deficiency (insufficiency) is common (ages > 11): > 30% deficient (less than 20 ng/ml 25-OH-D) > 70% insufficient (less than 32 ng/ml 25 OH-D) Target levels are controversial 30-50 ng/ml Sun absorption/exposure varies greatly Treat for 2-3 months, discuss ongoing dose