DEXA bone densitometry is a simple, non-invasive procedure. Once on the table you may be asked to hold an awkward position for a short time while the arm of the machine passes over your body taking measurements. It is important that you stay as still as possible during the procedure to ensure a clear, useful image. No anaesthesia is required. The procedure is painless and radiation exposure is minimal.

The DEXA bone density test takes 10 to 30 minutes, depending on the equipment used and the parts of the body being examined. You may be asked to undress and put on a hospital gown. Then you'll lie on a padded table with an x-ray generator below and a detector (an imaging device) above. Most often, doctors focus on bone loss in the spine and hip where most osteoporosis-related fractures happen. The detector is slowly passed over the area, generating images on a computer monitor.

The results of a DEXA bone density exam are interpreted by a radiologist or radiographer, who is specially trained to diagnose conditions and diseases by obtaining and interpreting medical images and these results are then sent to the referring doctor. If you were referred by a hospital consultant your GP will also receive a copy of the report.

The test results will be in the form of two scores:

• T score — this number shows the amount of bone you have compared with a young adult of the same gender with peak bone mass. A score above -1 is considered normal. A score between -1 and -2.5 is classified as osteopenia, the first stage of bone loss. A score below -2.5 is defined as osteoporosis. It is used to estimate your risk of developing a fracture.
• Z score — this number reflects the amount of bone you have compared with other people in your age group and of the same size and gender. If it is unusually high or low, it may indicate a need for further medical tests.