Dual Energy X-ray Absorptiometry (DEXA) scan capabilities now include rat models. The DEXA Scan measures body composition, bone mineral content, bone area, bone mineral density (BMD), percent body fat, and percent lean tissue. It uses X-ray technology while delivering a much smaller dose of radiation than a standard chest X-ray. The assay aims two X-ray beams with differing energy levels at a target (i.e., rat bones), and measures the absorption of each X-ray beam by the target. BMD is determined after subtracting out soft tissue absorption. Using the same technology, DEXA Scan can also measure total body fat content and total lean tissue content, making this assay useful for phenotyping models of osteoporosis, obesity, and metabolic syndrome. DEXA scanning also is available for mice.