Northwestern Medical School will be one of about 20 centers worldwide to test an experimental system for detecting cervical cancer that is thought to be a more accurate and faster technique than the Pap smear.

InPath, created by the Chicago-based Ampersand Medical Corporation, will use a “cocktail” of protein-based probes to find abnormal cells, said Eric Gombrich, the company’s vice president. The cells would be identified on a computer instead of a microscope, he said.

But the method for cell collection is less important than the test’s reliability, said David Fishman, a professor at the Medical School and participant in the InPath trial.

“What they’re doing is offering a more accurate diagnosis, not a revolutionary way of collecting cells,” he said.

The Medical School, which has been researching the InPath procedure for four years, will ask patients who come in for a Pap smear if they would like to receive the experimental test in addition to the Pap smear.

The InPath procedure could mean a variety of benefits for patients, Gombrich said.

More accurate testing could save time for patients who would have to return to their doctors because of inaccurate testing, he said. Some women must return if their Pap smear results are inconclusive, and getting the results can take anywhere from two days to three weeks.

But InPath can generate results in 20 minutes, Gombrich said. This allows patients who receive abnormal results to be retested while they are still in the doctor’s office instead of having to schedule another appointment.

The speed of the examination also will help doctors diagnose those patients whose tests appear abnormal, he said.

“The laboratory will get to spend more time on the abnormal samples to provide a more accurate diagnosis,” Gombrich said.

InPath uses a balloon-like device covered in the protein-based probes to remove cells from the cervix. The probes, which have florescent tags, bond to abnormal cells and direct computers to affected areas.

“This will provide more comfort for the patient, less bleeding after the procedure,” Gombrich said.

Without insurance, the procedure will cost half the price of the current Pap smear, he said.

The testing probably will focus on women who have had abnormal Pap smears in the past, Gombrich said. Because InPath is still experimental, all women who receive it also will get regular Pap smears.

Gombrich said InPath will be ready for use in the United States as early as the end of the year.