Dexa stands for ‘Dual Energy X-ray Absorptiometry’. It is the most commonly used test for measuring bone mineral density. It is one of the most accurate ways to diagnosis Osteopenia or Osteoporosis. This test can also be used to follow and monitor your treatment plan.
The National Osteoporosis Foundation’s guidelines state that women over 65, younger post menopausal women who have any of the osteoporosis risk factors , as well as those with specific fractures. However, men are also at risk for Osteoporosis as they age – especially if they have some of the causes of Osteopenia or Osteoporosis.
You should not have the test if you are pregnant or think you are pregnant. Also if you have had another X-ray with contrast media in the last 7 days (some examples: barium enema, upper GI , some CAT scans] or if you have had a nuclear scan (including bone scan and thyroid study) in the last 7 days, you should not have this test.
Dexa Scans are used to measure bone mineral density because they:
- Are more accurate than regular X-rays. A person would need to lose 20-30% of their bone density before it would show up on an X-ray.
- Requires less radiation exposure than CAT scans or Radiographic Absorptiometry. In fact you are exposed to more radiation on a coast to coast airline flight than you are during a dexa scan.
- Are less costly that other tests.
This is a non-invasive test and requires very little preparation. If you are taking calcium supplements, stop taking them for 48 hours before your test. If you are taking any medications for Osteopenia or Osteoporosis, do not take them the day of your test. You can eat and drink normally on the day of the test. Do wear loose clothing that has no metal zippers, metal buttons etc. (or you will need to disrobe).If you wear any kind of metal jewelry, you will need to remove it before the test.
Be sure to tell the technician if you have had any hip or back injury. And since most technicians will measure the hip of your non-dominant hand, it is worth mentioning if you are left handed.
Most insurance companies will pay for the test – especially if you have any of the risk factors. Do check with your insurance company.
Medicare will cover an initial screening and a repeat screening once every 24 months. If your DEXA scan shows osteoporosis and you begin taking a prescription medication to treat this condition, Medicare will cover a repeat scan after 1 year to see if the treatment is working. Repeat screenings are covered every 2 years.
- Patients who have thin bones or certain fractures.
- Patients taking more than 7.5mg of prednisone per day.
- Patients with an over-active thyroid.