BREATH TEST FOR ULCERS MAY EASE DIAGNOSTIC PROCEDURE.

Byline: Jody A. Charnow Medical Tribune News Service

A simple breath test that detects ulcer-causing bacteria may spare many people the inconvenience of an invasive procedure.

The U.S. Food and Drug Administration recently approved the Meretek breath test for diagnosing infection with Helicobacter pylori, the bacterium that scientists believe is responsible for most peptic ulcers. The test has an accuracy rate of 95 percent and is expected to be available to doctors this fall.

A person undergoing the test drinks a new diagnostic drug called Pranactin, then exhales breath samples into balloonlike containers.

Doctors then send the breath samples to laboratories operated by Meretek. Test results are available within 24 to 48 hours after the laboratories receive the samples, according to a company spokesman.

The test, which takes about half an hour to administer, is expected to reduce dramatically the number of people who undergo a procedure called endoscopy, which involves inserting a tube into a person's stomach and duodenum, the first portion of the small intestine. The tube enables doctors to inspect the lining of the stomach and duodenum and to obtain a tissue sample that can be tested for H. pylori. The procedure commonly requires people to take a day off from work and to be sedated.

Endoscopy must be done by a doctor trained in the procedure, usually a gastroenterologist, but, said Dr. Mae Go, assistant professor of medicine at Baylor College of Medicine in Houston, ``anyone can use the breath test.''

Most people younger than 50 who have peptic ulcer symptoms and who test positive for H. pylori with the breath test can be treated for H. pylori-associated ulcers without having to undergo endoscopy, said Dr. Bergein F. Overholt, a gastroenterologist in Knoxville, Tenn., who has used the test on patients.

Pain around or above the navel, especially after meals, is a key symptom of peptic ulcers, which, according to researchers, afflict an estimated 10 percent of people in the United States at some point in their lives.

In addition, the breath test provides doctors with an easier way to monitor the effectiveness of anti-H. pylori treatment, which typically consists of antibiotics in tandem with acid-suppressing drugs, Overholt said.

Go agreed. ``One of the real important uses of the test will be confirmation of cure,'' she said.

And Overholt said he believes that the cost of the test probably will be one-third to one-half that of the complete cost of an endoscopic procedure.

The breath test is based on H. pylori's ability to break down urea, the active ingredient in Pranactin. H. pylori breaks down urea in a process that produces carbon dioxide, a gas that people exhale in their breath. The urea in Pranactin, however, is composed of a form of carbon called carbon 13, which is not commonly found in breath.

When H. pylori breaks down the urea, carbon dioxide containing the carbon 13 is formed. This carbon dioxide enters the blood and travels to the lungs, where it is exhaled.

A sophisticated instrument is used to measure the amount of carbon 13 in two breath samples from patients - one sample obtained before Pranactin is taken, and the other obtained after the drug is swallowed. Higher levels of carbon 13 in breath after the drug is swallowed indicate H. pylori infection. The test identifies H. pylori infection accurately in 95 percent of cases, an accuracy comparable to that of the biopsy test, Go said.

The breath test may pick up infections that could be missed by biopsy tests, according to Go. H. pylori bacteria are not uniformly distributed in the stomach and duodenum, she explained. Biopsy specimens may be taken from a site that contains no bacteria or not enough bacteria to give a positive test result.

The breath test may circumvent that problem. ``The drug Pranactin coats the stomach, so no matter where the bugs are, you're going to find them,'' Go said.

But endoscopy still has a place in ulcer care, the experts said. For example, endoscopy may be necessary for people with peptic ulcers that fail to respond to treatment or who may have signs of more serious illness.