Bone density tests (also called bone mineral density tests or BMD tests) check how strong your bones are by measuring a small part of one or a few of them. The results can help your doctor know how you can treat or prevent bone loss and fractures.
Who Should Have a Bone Density Test?
According to the U.S. Preventive Services Task Force, BMD tests are recommended for:
- All women ages 65 and older
- Younger women with a higher-than-normal chance of fracture for their age
Types of Bone Density Tests
Two types of machines can measure bone density. Central machines test it in the hip, spine, and total body. Doctors can use them to do different types of bone density tests:
- DXA (dual-energy X-ray absorptiometry) measures the spine, hip, or total body. Doctors consider this test the most useful and reliable for checking bone density.
- QCT (quantitative computed tomography) usually measures the spine, but it can test other sites, too. You usually get this test to see how well osteoporosis treatments are working.
Peripheral machines check the finger, wrist, kneecap, shinbone, and heel. These machines are a good option when DXA scans aren’t available. But DXA scans are still the best choice for screening. Peripheral screening tests include:
- pDXA (peripheral dual-energy X-ray absorptiometry) measures the wrist or heel.
- SXA (single-energy X-ray absorptiometry) measures the wrist or heel.
- QUS (quantitative ultrasound) uses sound waves to measure density, usually at the heel.
- pQCT (peripheral quantitative computed tomography) measures the wrist.
- RA (radiographic absorptiometry) uses an X-ray of the hand.
Once you get your test results, you and your doctor can decide what to do next.
Does Insurance Cover It?
Most health insurers will pay for the test if you have one or more things that raise the chances you have osteoporosis, such as:
- A fracture
- You’ve been through menopause
- You’re not taking estrogen at menopause
- You take medications that cause bone thinning
Medicare covers bone density testing for specific types of people ages 65 and older:
- Women whose doctors say they’re low in estrogen and at risk for osteoporosis
- People whose X-rays show they may have osteoporosis, osteopenia, or spine fractures
- People who take steroid medicines or plan to start
- People with primary hyperparathyroidism
- People being monitored to see if their osteoporosis drugs are working
Medicare will pay for a bone density test every 2 years.
Do I Need Bone Density Tests to Check on My Osteoporosis Treatment?
Doctors disagree on this question. The American Medical Association and other major medical groups say that most people don’t need repeat testing to check on their osteoporosis treatment in the first 3 years. Bone density changes so slowly with treatment that the differences may be smaller than the measurement error of the machine. These experts say that repeat scans can’t tell the difference between a real increase in bone density due to treatment and a change in how the machine measures it.
But other groups like the National Osteoporosis Foundation still support repeat testing every 1 to 2 years during treatment. Ask your doctor what is right for you.
Most doctors call for repeating the test in 2 years after you have it the first time. They do it to see if your medication is working.