What is a T-score or Z-score?

A T-score is when the bone mass or density is then calculated and compared to the peak bone mass of a controlled population at age 30.  A normal T-score is -1 and above.  A low bone mass is between -1 and -2.5.  Osteoporosis is defined as a T-score of -2.5 or lower.  A Z-score is a calculation comparing the bone mass of a similar patient at a similar age.