Initial screening for osteoporosis should be performed according to National Osteoporosis Foundation (NOF) recommendations. The optimal interval for repeating DEXA scans is uncertain, but because changes in bone density over short intervals are often smaller than the measurement error of most DEXA scanners, frequent testing (e.g., < 2 years) is unnecessary in most patients. Even in high-risk patients receiving drug therapy for osteoporosis, DEXA changes do not always correlate with probability of fracture. Therefore, DEXA should only be repeated if the result will influence clinical management or if rapid changes in bone density are expected. Recent evidence also suggests that healthy women 67 years and older with normal bone mass may not need additional DEXA testing for up to 10 years provided osteoporosis risk factors do not significantly change.