Some 15 million Americans get prodded with flexible endoscopes each year. These sleek devices have huge advantages over scalpels. They can snake deep into the lungs or the colon, using lights and fiber optics to illuminate problems that used to show up only during exploratory surgery. Doctors can even insert tiny instruments through a scope’s open channels to biopsy lung tumors, remove gallstones or snip polyps from the bowel. But flexible endoscopes are hellishly difficult to clean. Blood and other bodily material can lodge in the channels. And though there are strict guidelines for disinfecting scopes, it’s not at all clear that the job is getting done. ““You wouldn’t have unprotected sex,’’ says Los Angeles lawyer Raymond Boucher, whose client was apparently infected with human papilloma virus during a routine colonoscopy. ““Why should you submit to unprotected medicine?''

No one knows how often endoscopes transmit serious illnesses, such as hepatitis or pneumonia. Citing reported statistics, some experts maintain that only 1 endoscopy in 1.8 million results in infection of any kind. ““In every instance I’m aware of, it’s been the result of major breaches of standards,’’ says Dr. Juergen Nord, president of the American Society for Gastrointestinal Endoscopy. ““These procedures have an unsurpassed safety record.’’ But critics say the official reports understate the rate of infection. A patient won’t necessarily link a fever to an earlier procedure–and medical institutions aren’t eager to report the cases they do know about. ““Administrators are afraid of lawsuits,’’ says Walter Bond, a former hospital-infections expert at the Centers for Disease Control and Prevention. Moreover, the cleaning standards that Nord touts are easy to breach.

The basic problem with scopes is that, unlike most surgical equipment, they can’t be heat-sterilized. Their delicate tubes, valves and optics would disintegrate under the high temperatures and pressures. So technicians must painstakingly scrub the scopes manually with tiny brushes, then disinfect them–usually by soaking them in a chemical called glutaraldehyde for at least 20 minutes. But technicians don’t always do a thorough job. Endoscopes have valves and joints that are nearly impossible to scrub, not to mention channels that are two to six feet long and just millimeters wide. If any debris is missed, the glutaraldehyde solution doesn’t remove it. Rather, it hardens the debris, leaving it there to be chipped off in later procedures and passed to other patients. An FDA-funded study in 1995 reported that nearly half of 80 facilities examined had at least one ““patient-ready’’ scope whose open channels were ““visibly encrusted with debris.’’ An older study of 26 institutions found that almost a quarter of cleaned scopes had culturable bacteria in them.

Fortunately, manufacturers are continually improving scopes and cleaning methods to reduce the risk of infection. But David Lewis, a research microbiologist at the University of Georgia, isn’t willing to wait. He is waging a campaign for doctors to start sterilizing their scopes now–not merely disinfect them. There are two technologies on the market today that meet his standards. The first is a high-tech washing machine from Steris Corp. in Mentor, Ohio. Instead of merely soaking the instruments, it blasts them with a compound called peracetic acid. The scopes still require meticulous scrubbing beforehand. But Lewis says the acid eats through any remaining debris. (He does consulting for Steris, but donates his fees to charity.)

The other approach is to create a barrier between the scope and the patient. Vision Sciences, a firm based in Natick, Mass., has developed a ““sheathed’’ endoscope–think of it as a scope with a condom. Doctors can reuse the expensive optics and hardware. But after each use, they replace the inexpensive outer sheathing and the inner channels that ““patient material’’ passes through. Some doctors have found the sheathed scopes harder to handle. But the reduction in risk–and the ease of cleaning–compensate.

It may seem that patients are defenseless. But they’re not. The surest way to avoid infection is to seek out a facility that either sterilizes with peracetic acid (about 20 percent of hospitals) or uses sheathed scopes (a small percentage of docs). If no one in the area does, at least make sure that the facility you choose isn’t taking shortcuts on disinfection. Your best bet is to try a large endoscopy center or outpatient surgery center, where technicians are dedicated just to cleaning scopes. Ask if the facility has written guidelines conforming to those of ASGE. And ask how long technicians take to disinfect the scopes. ““It should never take less than half an hour,’’ says Dr. Johannes Koch of San Francisco General Hospital. ““If it’s 15 minutes, you don’t go there.’’ The one thing not to do is avoid endoscopies out of fear of contamination. They could save your life.