The Dual-Energy X-ray Absorptiometry (DEXA) scan may be scheduled prior to the start of the GFR measurement or following the entire GFR visit if timing is best for the participant and the DEXA scan. It may be performed on a separate day. Prior to the scan, subjects will be asked to remove any metal objects (e.g. belts, earrings, jewelry, etc). Subjects may be requested to void prior to initiating the scan. During the scan, subjects will be asked to lie flat on the table for approximately 5-10 minutes while the scan takes place.