text_1: Definitive tests for irritable bowel syndrome developed at Cedars-Sinai: New blood tests will speed up diagnosis for the most common GI disorder
text_2: Image from ibschek.com The release states that two “simple” new blood tests can be used to diagnose irritable bowel syndrome (IBS) by detecting antibodies that signal the presence of toxins that can cause IBS. This diagnosis, in turn, would allow patients to receive treatment more quickly. But the release has many problems that start with the headline, which claims there is now a “definitive” test for IBS. That’s an exaggeration, as the findings need further validation and they apply only to a subset of patients with diarrhea as their main symptom — something the release never explains. The release also glosses over some significant points — such as the fact that there were only 43 control patients (too small a group to draw “definitive” conclusions), and that there’s no evidence that treating patients based on these test results will actually improve their outcomes. The cost of the test and its potential harms — e.g. false-positive results that lead to unnecessary or misguided treatment — also aren’t explored in any way. [Editor’s note: We’ve also published a review of a CBS News story about the test that shares many of the same shortcomings as this release.] While it’s not clear how many people suffer from IBS, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD) reports that IBS affects at least 3 percent of the adult population — and probably closer to 10 or 15 percent of the adult population. The term “IBS” refers to a range of bowel symptoms including pain, constipation, and/or diarrhea. IBS is not meant to represent a single underlying cause, but in fact may represent a number of different conditions that result in functional bowel symptoms. This news release refers to an attempt to develop a test to better categorize certain patients with IBS. Though the news release implies the test is for all patients with IBS, in fact it evaluated two tests for individuals with IBS who had diarrhea as the predominant symptom. The implication that these tests may provide a diagnosis for IBS more broadly is not correct. Whether these tests hold up as being accurate when applied more broadly to patients with IBS and other related bowel conditions remains to be proven. It would also be important to see how common the test is positive in individuals without chronic bowel symptoms. Finally, even if these tests are specific for individuals with diarrhea-predominant IBS, it’s unclear if it would make any difference in their treatment or lead to a reduction in the severity of symptoms. That’s a premise that still needs to be tested.