The T-score and Z-score in a bone density test are two important indicators. The T-score compares your bone density to the average peak bone density of a healthy young adult, and it is used to assess the risk of osteoporosis. The Z-score compares your bone density to the average bone density of people of the same age and gender. There are several methods for bone density testing, with the most common being Dual-energy X-ray Absorptiometry (DXA), which accurately measures bone density. Other methods include Quantitative Computed Tomography (QCT) and Ultrasound Bone Densitometry. Each method has its pros and cons, but DXA is widely considered the standard and most reliable.