Read an Excerpt
Chapter 2: Bone Density Screening — Right Test, Wrong Results?
If your car’s fuel gauge is off, the worst that might happen is you’d run out of gas and need a tow — or a battery charge, if the car’s electric. But if the tools used to gauge your health malfunction, the consequences are much more serious. Unfortunately, when it comes to evaluating fracture risk, bone density testing procedures can be off the mark. And that can result in your getting the wrong diagnosis, the wrong treatment plan, or unnecessary medications.
Consider what happened to Ellen, a woman in her sixties who’d had several bone density tests over the years because of concerns about osteoporosis.
Positioning Error Leads to Prescription for Fosamax: Ellen’s Story
Ellen called me from her home on the East Coast after a mutual friend recommended she ask me to assess her latest bone density test. Just listening to her story over the phone, I could tell that something was not right regarding the reported findings of her test. The most recent exam showed that Ellen had lost 7 percent of the bone density in her hip since her previous test a year earlier, but her spine remained unchanged. The discrepancy raised a red flag for me. As a densitometrist, I know that it is highly unusual to see such an extreme loss in the hip, especially within one year.
My suspicions were confirmed when I sorted through the stack of paperwork Ellen sent and after I reviewed each of her bone density scans. Comparing the two most recent tests, I could tell that the first technician had failed to position Ellen’s hip properly (using a fifteen- to twenty-degree internal rotation), while in the second test the hip was properly positioned.
Why does hip rotation matter during a bone density test? If the hip is incorrectly positioned, errors in density readings of up to 10 percent can occur. That can make the difference in whether or not a doctor recommends medication, as bone loss is a trigger for prescribing drugs. It could also make the difference in whether or not a person is diagnosed with osteoporosis. In Ellen’s case, the mistake led to an erroneous report of a 7 percent bone loss, which, understandably, made her very upset.
What’s worse, none of it should have happened. In Ellen’s first bone density test, the technologist’s failure to properly rotate her hip should have been caught and corrected before the report was made — if not by the technologist then by the reporting doctor handling the test. Then, for Ellen’s second test, the technologist did rotate her hip correctly, but failed to note the error from the previous test. This is the mistake that resulted in the report of an apparent 7 percent bone loss in Ellen’s hip. Compounding the problem, the doctor who wrote the report on the second test results did not catch the mistake either. If the test results were truly showing such a significant change in her bone density, Ellen’s own physician should have ordered lab tests to investigate the problem further, but that did not happen; instead, she was prescribed Fosamax, a drug for treating osteoporosis. Believing that the reports were accurate, most medical doctors would likely have done what Ellen’s physician did, which was to recommend medications solely on the basis of apparent bone loss.
Once I was able to guide Ellen in getting an accurate bone density reading, we discovered that her bone was stable — meaning no active loss of bone. Additional lab tests verified this finding. To date, she has been able to maintain her bone stability by following a bone-healthy nutrition and exercise program that includes appropriate nutritional supplements — and currently she has no need for osteoporosis medications.
I wish I could tell you that Ellen’s case is unusual. But it’s not. I see similar bone density testing errors over and over when consulting with my patients. These problems are common knowledge among those trained in densitometry. We all know that preventable mistakes are being made. Why does this happen?
