Bone Density Testing measures the patient’s bone mass at the time of the study it is an x-ray procedure and requires a doctor’s order. A VFA (vertebral fracture assessment) should be done to evaluate the presence of undetected compression fractures as this could change your classification according to the WHO criteria which could change the doctors clinical decision making as to treatment and follow-up.

A patient should not take any calcium for 24 hours before the test and should not have a nuclear procedure within 10 days of the test as this may interfere with the results. This requires the patient to lie down approximately 30 minutes while different sites such as the hip and spine are scanned. Additionally, a fore arm study is helpful in evaluation.

The bone changes at different sites at different rates. Cortical bone changes slower than Trabecular bone in bone remodeling.

The results reveal both T-scores and Z-scores and both should be evaluated if treatment is necessary by the ordering physician.

Instructions Before Your Test

  1. Please do not take any calcium tablets for 24 hours prior to your test. Calcium tablets may not be fully absorbed and may affect the results.
  2. Please do not wear clothing that contains metal such as underwire bras, rivets, or zippers. This would create artifact that would make the test results inaccurate.
  3. If you choose to wear pants or shorts, please make sure they have either an elastic waist or buttons.
  4. Please let us know if you have had a recent nuclear medicine / barium study as you will need to wait at least 10 days before having a DXA. Contrast or dye will interfere with the machines ability from being able to differentiate the skeleton from the contrast or dye.
  5. If you have had prior bone density tests, please let us know the date and location. This will allow us to give you a more complete evaluation. To properly compare images the patient should be aligned as closely to the prior scan as possible before the scan is acquired.
  6. Please bring your test order with you along with your insurance card/s. This is a low dose x-ray procedure as such a doctor or a nurse practitioner’s order is needed before a machine is turned on to begin the study.


Prescreening Article for Who Needs DXA?

Hologic Discovery Page




Sign up for a FREE email list.

* Get breaking medical news and clinical perspectives on Osteoporosis & Skeletal health.
* Unlimited access to the Annual Meeting medical education course videos.

The Northern California Institute for Bone Health, Inc., is dedicated to detection of bone loss and improvement in treatment utilizing bone density testing, clinical research and education of physicians, allied health professionals and the general public.  Join us!