What Exams and Tests Do Health-Care Professionals Use to Diagnose Osteoporosis?
The doctor will usually begin with a careful history to determine if you have osteoporosis or if you may be at risk for the disease. You will be asked a variety of questions regarding lifestyle and other conditions that you may have. The doctor will also ask if you have a family history of osteoporosis or a history of previous broken bones. Often blood tests are used to measure calcium, phosphorus, vitamin D, testosterone, and thyroid and kidney function.
Based on a medical examination, the doctor may recommend a specialized test called a bone mineral density test that can measure bone density in various sites of the body. The diagnosis of osteoporosis or osteopenia can be made based on the results of these tests. Osteopenia is lower-than-normal bone density not severe enough to be classified as osteoporosis and is considered by many experts to be a precursor to osteoporosis. A bone mineral density test can detect osteoporosis before a fracture occurs and can predict future fractures. A bone mineral density test can also monitor the effects of treatment if the tests are performed a year or more apart and may help determine the rate of bone loss.
- Several different machines measure bone density. All are painless, noninvasive, and safe. They are becoming more readily available. In many testing centers, you don't even have to change into an examination robe. Central machines may measure density in the hip, spine, and total body. Peripheral machines may measure density in the finger, wrist, kneecap, shinbone, and heel.
- The DXA (dual-energy X-ray absorptiometry) measures the bone density of the spine, hip, or total body. With your clothes on, you simply lie on your back with your legs on a large block. The X-ray machine moves quickly over your lower spine and hip area.
- SXA (single-energy X-ray absorptiometry) is performed with a smaller X-ray machine that measure bone density at the heel, shinbone, and kneecap. Some machines use ultrasound waves pulsing through water to measure the bone density in your heel. You place your bare foot in a water bath, and your heel fits into a footrest as sound waves pass through your ankle. This is a simple way to screen large numbers of people quickly. You might find this type of screening device at a health fair. Bone loss at the heel may mean bone loss in the spine, hip, or elsewhere in the body. If bone loss is found in this test, you might be asked to have the DXA to confirm the results and get a better measurement of your bone density.
- The result of the bone mineral density is compared to two standards, or norms, known as "age matched" and "young normal." The age-matched reading compares your bone mineral density to what is expected of someone of your age, sex, and size. The young normal reading compares your density to the optimal peak bone density of a healthy young adult of the same sex. The information from a bone mineral density test enables the doctor to identify where you stand in relation to others your age and to young adults (which is presumed to be your maximum bone density). Scores significantly lower than "young normal" indicate you have osteoporosis and are at risk for bone fractures. The results will also help the doctor to decide the best way to manage your bone health. For patients who have borderline results, an especially helpful new method of determining the 10-year probability of fracturing bone can be determined using a program called FRAX. This computation method is available online and takes into account all risk factors for a given individual to determine their personal risk for fracture and, therefore, need for treatment.
Medically Reviewed by a Doctor on 4/27/2016
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