March 10, 2000

New Pap smear provides more accurate test results

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Nurse Practitioner Beth Colvin Huff demonstrates the new method for obtaining and evaluating Pap smears. (photo by Dana Johnson)

New Pap smear provides more accurate test results

A new type of Pap smear available at Vanderbilt University Medical Center is improving the odds of spotting early cervical cancer and other abnormalities in the cervix.

The new Pap smear test, called ThinPrep, is more sensitive, more accurate and easier to read, said Dr. Howard W. Jones III, professor of Obstetrics and Gynecology.

"It is more accurate than the traditional Pap smear, with much cleaner smears with less background."

Pap smear screens are used to find cervical cancer and pre-cancerous conditions in the cervix, which, if spotted early enough, are highly treatable, Jones said.

"Cervical cancer still kills more women on this planet than any other kind of cancer, but in our country and in most of the developed world that is no longer true. And that is no longer true because of Pap smear screening," Jones said.

"It's estimated that the death rate from cervical cancer has decreased 70 percent as a result of Pap smear screening and if women were to get their Pap smears the way that they are supposed to, it would be decreased by 90 percent."

The new Pap test is obtained during a routine pelvic exam. Specimens are collected using a spatula and brush to obtain cells from both outside and inside the cervix, similar to the conventional Pap smear method.

But the preparation of the specimen with the new method is different from conventional Pap smears.

With the conventional glass slide technique, specimen cells are smeared on the slide and sprayed with a fixative before being sent to the lab for analysis.

"There were some problems with that because techniques can differ. Sometimes the slide can be smeared thickly or too thinly. If you hold the slide in the air too long or if you spread the material on the slide and let it sit there too long, the cells would become air dried and that changes the way they look under the microscope," said Beth Colvin Huff, M.S.N., nurse practitioner.

With the new Pap test, the specimen is mixed into a vial of liquid preservative, which is sent directly to the lab. The lab processes the specimen and makes the slide samples, providing a cleaner, more uniform sample for analysis, Huff said.

Jones said an international study proved the effectiveness of the ThinPrep method and a follow-up study of 10,000 women at VUMC and several other institutions in the United States confirmed its usefulness.

"The research showed there were fewer patients who had unsatisfactory smears and we had more patients with definitely abnormal smears. It helps us avoid incorrect diagnoses and misinterpreted results," Jones said.

The follow-up research showed also a higher number of confirmed abnormalities, Jones said. The cost of the new testing method is slightly higher than a standard Pap smear.

Jones said it is recommended that every woman have a Pap smear once a year.