A million things can go through your head when you get the results of a biopsy from your doc. But asking if the results belong to you probably isn’t one of them—though new research suggests that maybe it should be. Turns out getting someone else’s results isn’t exactly rare. After a biopsy is collected at a doctor’s office, it goes through several steps. The biopsy is transported to a pathology lab, processed, turned into a glass slide, and then delivered to a pathologist who writes up a report. All said and done, it takes around 20 steps—in different buildings and sometimes across state lines—to reach a diagnosis. “It’s very complicated,” says John Pfeifer, MD, PhD, professor of pathology and immunology at Washington University School of Medicine in St. Louis. “It’s clear there are multiple opportunities for errors to occur, and nobody really had an idea of how often that was happening.” So Dr. Pfeifer decided to find out just how rampant biopsy mix-ups are. In a new study published in the American Journal of Clinical Pathology, he and a colleague analyzed data from about 13,000 prostate biopsies, provided by a private lab called Strand Diagnostics. (The company also markets a system that can detect whether the biopsy matches the DNA of the supposed patient.) More from Prevention: 20 Ways To Prevent Cancer The team scoured the data for two types of errors: Type-1 errors indicate a complete sample swap between patients, and type-2 errors result from tissue contamination from one or more other samples. Of those 13,000 samples, researchers found a total error rate of less than half a percent, which translates to around 5 patients in 1,000, Dr. Pfeifer says. More data is needed to find out if the study is representative on a larger scale, but if it is, those numbers would metastasize: About 1 million prostate cancer biopsies occur annually, so this error rate would affect close to 5,000 people. Breast biopsies, which travel the same test cycle as prostate biopsies, occur 1.6 million times a year. In reality, the error rates are at least twice as high, Dr. Pfeifer speculates. For every patient linked to the wrong biopsy, there’s another patient in the same boat (whose sample wasn’t retested for accuracy.) And sometimes, samples are mixed or contaminated between three or more patients, he says. The costs of these mix-ups can be huge, sometimes resulting in unnecessary surgery or chemotherapy (not to mention heaps of liability for medical practitioners). Unfortunately, there’s no simple tweak to the complex analysis process that can remedy the dilemma. “I can simply say that in my over 20 years of experience in this business, we’ve seen it occur at virtually every single one of those steps,” Dr. Pfeifer says. The good news? You can ensure that your biopsy results really are yours. Some practitioners are now using DNA testing to ensure that specimens belong to the right patient. One laboratory providing these services is Strand Diagnostics, which provided the samples for this research. For now, the test isn’t standard, though it is being adopted by an increasing number of physicians (more than 1,100 doctors participate in Strand’s program). Ask for the procedure at the time of your biopsy, and check with your insurance company—several large providers cover it in full. More from Prevention: The Cancer Screenings Every Woman Needs Questions? Comments? Contact Prevention’s News Team!
