How to Measure Bone Mass Index

Bone mass index, also commonly referred to as bone mineral density (BMD), is an important number that is used when assessing overall bone health. The bone mass index, coupled with other health exams, gives a physician an idea of how healthy the bones are, whether or not the bones are suffering from osteoporosis, and how likely severe problems such as fractures as a result of low density are to occur. Measuring and interpreting bone mass index requires skill and practice.

Instructions

• 1

  Perform a dual energy x-ray absorptiometry (DXA), peripheral dual energy x-ray absorptiometry (pDXA), quantitative ultrasound (QUS), quantitative computed tomography (QCT), or peripheral quantitative computed tomography (pQCT) test. These tests measure the bone density at various points of the skeleton. Advise the patient to remove all jewelry before having the test performed.

• 2

  Read the T score produced by the test. A T score of -0.99 or higher is normal. A T score of -1 to -2.5 indicates that bone loss, also known as osteopenia, is starting to occur. A T score of -2.6 or lower indicates more severe bone loss and a diagnosis of osteoporosis.

• 3

  Read the Z score. The Z score compares the patient's bone mass to the average mass of a person with the same age, gender, and race of the patient. A Z score of 0 indicates that the patient's bone mass is the same as the average person with the patient's same age, gender, and race. A Z score of greater than 0 means that the patient's bone's are more dense than average. A Z score of lower than 0 means that the patient's bones are less dense than average.