The test throws up too many false-positives-'seeing' cancerous or abnormal tissue that is actually healthy-and so an annual test has become an outdated practice, say researchers.
Instead, doctors are advised to carry out a smear test only once every three years on women aged from 21 to 69 years.
But a study has discovered that doctors are still offering an annual Pap test, mainly as a way to encourage women to visit the surgery once a week so that other checks can also be performed.
An abnormal Pap result triggers a series of further, and more invasive, tests. A colposcopy, where the cervix is examined more closely, and a biopsy, where a sample is taken, are often the next steps. A biopsy can cause pain and bleeding, and the woman has to live with the stress of a possible cancer diagnosis for months.
But, as researchers from the University of North Carolina say, too many Pap test results are false-positives. It's enough that women aged from 21 years have a Pap test once every three years, while those aged between 30 and 65 could have one every five years.
(Source: American Journal of Preventive Medicine, 2013; 45: 248-9).