Exams and Tests for Osteoporosis

By knowing, monitoring, and protecting your bone health, you can potentially avoid an osteoporosis diagnosis, or worse, a vertebral compression fracture. If you think you might be at risk for this bone disease, you should be proactive. Otherwise, most people find out they have osteoporosis when they break a bone.
Doctor showing an x-ray to an older female patientTo find out your BMD, your doctor will use a special type of x-ray called dual-energy x-ray absorptiometry (DXA).

Who Should Be Tested for Osteoporosis?

  • Someone who has an x-ray that reveals low bone mass, which could mean osteopenia or osteoporosis
  • Women who begin menopause before age 45 and who are not taking estrogen (eg, estrogen replacement therapy or ERT)
  • Women age 65 or older
  • Post-menopausal women who have one or more of the osteoporosis risk factors—and especially a history of fracture
  • Men age 70 or older
  • Men age 70 or younger who have one or more of the osteoporosis risk factors
  • Family history of osteoporosis
  • Steroids have been (or are) taken regularly
  • Diagnosis of hyperthyroidism, diabetes, liver/kidney disease, and/or rheumatoid arthritis

Bone Densitometry Test Measures Bone Mineral Density

One of the best and most common ways to monitor your bone health is by having a bone densitometry or bone mineral density (BMD) test, also called dual-energy x-ray absorptiometry (DXA or DEXA). The test will let you know how strong—how dense—your bones are in particular areas (eg, hip, spine). In conjunction with these bone density tests, is the FRAX® fracture risk assessment tool that can help your doctor predict your likelihood of developing a fracture. Repeated testing allows the doctor to compare the results over time periods to see if you're losing bone or maintaining it.

A BMD or DEXA test is also used to confirm an osteoporosis diagnosis; in fact, it's the test than can diagnose osteoporosis.

Whether you're having a bone densitometry to confirm osteoporosis or you just want to monitor your bone health, the actual test is done in the same way. To find out your BMD, your doctor uses a special type of x-ray called dual-energy x-ray absorptiometry (DXA or DEXA). He or she will most likely scan your hip or your spine because they are most prone to fracture.

The whole test doesn't take long—maybe 5 to 10 minutes. Radiation exposure is minimal, and your results are often available the same day.

T-score and What It Means

Your doctor analyzes your bone density and assigns it a T-score. A T-score is a number derived by comparing your DEXA bone densitometry test results to an average score for a healthy adult of your gender and race who has reached their peak bone mass (usually around age 25).

The T-score signifies how far you are from "normal." It's the difference between your BMD and the BMD of someone at peak bone mass.

T-scores can be as low as one standard deviation (SD, a statistical term) below normal and still be considered healthy. Patients with T-scores between -1 SD and -2.5 SD have osteopenia and are considered at high risk for developing osteoporosis. Patients with T-scores lower than -2.5 SD have osteoporosis.

T-Score tableYour doctor decides how often to repeat the DEXA test. If you've already been diagnosed with osteoporosis, you may need it every year or two so that your doctor can determine if your treatments (eg, medication) are working properly. He or she will be able to tell that by comparing the T-scores.

Z-score and What It Means

Not everyone gets a T-score—you may get a Z-score. Women who haven't yet gone through menopause and men younger than 70 will still undergo bone densitometry using DEXA, but they will get a Z-score. Instead of comparing your bone mineral density to a 20-something adult, your doctor will compare it to the normal BMD for someone your age, gender, body type, and race.

Z-scores work just like T-scores: They tell the standard deviation from normal. If you have a low Z-score, your doctor may recommend further testing to see why you have low bone density. The ultimate goal is to understand your bone health and risk for osteoporosis before you break a bone.

Updated on: 08/10/18
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How to Start Your Osteoporosis Prevention Plan Today

Even if you have osteoporosis, these steps may help you keep strong bones and prevent spinal compression fractures.
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