How do I know which type of test should be ordered?
Tests for osteoporosis are either done to screen an individual to detect the presence of bone loss or done to monitor the progress of previously diagnosed bone loss. You may recall from Question 23 that the only tests used to diagnose osteoporosis are those that test the bone density of your spine or hip. Tests that are performed on peripheral limbs (hands, forearms, wrists, lower leg, and feet) are primarily used for screening. However, if you are obese, peripheral bone mineral density testing at the forearm is often used for diagnosis because most DXA machines are inaccurate for and cannot accommodate individuals who weigh more than 250 pounds.
The test that your clinician orders for you may be determined by many factors. Some of them are the availability of test sites and machines; your private insurance coverage or Medicare; and your individual medical situation, which includes your medical history, your risk factors for bone loss, whether you already have bone loss, and if you can travel to the specific testing site.
If you attend a health fair where you are screened for bone loss using a portable machine, there is not likely to be a choice of tests. And if the portable testing shows bone loss, your clinician may advise you to get a test of your spine or hip (DXA or QCT) to confirm a diagnosis of osteoporosis.
If you are reluctant to have a QCT due to the radiation or the expense, you should ask if there is an alternative test that could be done.
What if I live in a rural area and I cant get to a place with a DXA machine? Are there further tests that I would need?
DXA machines are the most widely available of all machines used for testing bone mineral density. However, some areas of the United States do not have access to DXA machines. Because it is important to have your bone density evaluated, particularly if you have risk factors for osteoporosis, you should still be evaluated using one of the screening tests that may be available in your area.
While it is preferable to have a test of your spine or hip to confirm a diagnosis of osteoporosis or determine if you have osteopenia, your clinician can still recommend preventive options and counsel you about nutrition and exercise for improving your bone health (see Part 3).
It usually takes about a 30% to 40% bone loss for osteoporosis to show up on conventional x-rays.
If you do not have access to any bone mineral density testing, it is still important to adhere to a regimen of weight-bearing exercises as well as a diet with sufficient calcium, vitamin D, and other nutrients to maintain healthy bones. You should also make every effort to prevent falls (see Question 79).
If I'm x-rayed for a broken bone, will osteoporosis, if I have it, show up on the x-ray? If it shows up on the x-ray, would I need further testing?
If you have advanced osteoporosis with significant bone loss, your x-rays may show osteoporosis. It usually takes about a 30% to 40% bone loss for osteoporosis to appear on conventional x-rays. Although x-rays are not used to diagnose osteoporosis, vertebral fractures are sometimes noted on conventional x-rays of the spine. If you have a chest x-ray, for example for pneumonia, vertebral fractures might be found incidentally, meaning that you may not have complained about them but they are nonetheless present and seen on the chest x-ray. Vertebral fractures noted on any type of x-ray are usually an indication that you have some degree of bone loss; however, further testing is still required after the fracture heals.
The fact that you have fractured a bone, particularly if it was due to a small amount of force or from a standing height or less, is more important in considering whether you need further testing for osteoporosis (see Question 74). It is important to establish a baseline of bone mass so that future therapies and treatments can be monitored for their effectiveness.
Any individual who has a vertebral (a bone in the spine) fracture or hip fracture is at high risk for osteoporosis, and while the fracture should be healed first (because fractures can sometimes interfere with the accuracy of DXA testing), further bone mineral density testing is still necessary. In case you are treated for any fracture through an emergency department or through a specialist, you should always update your primary care clinician about your fracture so that further testing can take place if necessary.