The ISCD (International Society for Clinical Densitometry) and the National Osteoporosis Foundation recommend that older adults (women over 65 and men over 70) and adults with risk factors for low bone mass, or previous fragility fractures, undergo DXA testing. The DXA (
dual X-ray absorptiometry) scan uses a form of X-ray technology, and offers accurate bone mineral density results with low radiation exposure. The United States Preventive Services Task Force recommends osteoporosis screening for women with increased risk over 65 and states there is insufficient evidence to support screening men. The main purpose of screening is to prevent fractures. Of note, USPSTF screening guidelines are for osteoporosis, not specifically osteopenia. The National Osteoporosis Foundation recommends use of central (hip and spine) DXA testing for accurate measure of bone density, emphasizing that peripheral or "screening" scanners should not be used to make clinically meaningful diagnoses and that peripheral and central DXA scans cannot be compared to each other. DXA scanners can be used to diagnose osteopenia or osteoporosis as well as to measure bone density over time as people age or undergo medical treatment or lifestyle changes. Information from the DXA scanner creates a bone mineral density
T-score by comparing a patient's density to the bone density of a healthy young person. Bone density between 1 and 2.5 standard deviations below the reference, or a
T-score between −1.0 and −2.5, indicates osteopenia (a T-score smaller than or equal to −2.5 indicates osteoporosis). Calculation of the T-score itself may not be standardized. The ISCD recommends using Caucasian women between 20 and 29 years old as the baseline for bone density for ALL patients, but not all facilities follow this recommendation. The ISCD recommends that
Z-scores, not T-scores, be used to classify bone density in premenopausal women and men under 50. ==Prevention==