A bone density test checks for osteoporosis, a disease that causes bones to become more fragile and more likely to break. In the past, osteoporosis could be detected only after you broke a bone. A bone density test makes it possible to know the risk of breaking bones before a break happens. At New Jersey Associates in Medicine we use X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. Knowing beforehand allows us to work with our patients to take the best course for treatment and accident prevention.