Researchers find that there’s little evidence to support most diagnostic tests for constipation.
Nearly everyone has had a bout of constipation -- infrequent bowel movements and difficulty passing stool -- at some point in their life. Constipation is not a disease, but rather a symptom that can stem from a number of medical conditions. Constipation becomes more common with age and occurs in at least 25% of people over age 65. In most cases, constipation is not a serious condition, and can be treated with lifestyle measures, such as increasing your intake of dietary fiber and level of physical activity or the short-term use of laxatives. In rare cases, surgery may be necessary to relieve symptoms of constipation.
When someone complains of chronic constipation, a gastroenterologist may perform a number of tests to identify the underlying cause of the constipation and the best way to treat it. But according to a study reported in the American Journal of Gastroenterology (Volume 100, page 1605), many of these tests are unnecessary.
To assess the value of various tests used to investigate constipation, researchers performed a search of the medical literature from 1966-2004. They found little or no evidence to support the routine use of blood tests, abdominal x-rays, sigmoidoscopies, colonoscopies, or barium enemas in people with constipation who do not have red-flag symptoms (such as rectal bleeding or unexplained weight loss).
There was, however, some evidence for the use of colonic transit tests (which measure the amount of time it takes for stool to move through the colon), anorectal manometry (which measures pressure in the rectum and anus), and balloon expulsion tests (which measure the ability of the rectum to expel feces). The researchers found that these three tests can reveal physical abnormalities that can lead to constipation. Still, no single test can identify the underlying cause of constipation in all patients, and several tests may be required to determine the exact cause of constipation and how to treat it.
