Pap smears are the Jekyll and Hyde of cancer screening tests. Laboratorians cite them as one of the cheapest, most effective cancer screening tools. Critics decry what they call their high false negative rates and labs’ shoddy screening practices. Pap smears are a major reason why cancer of the cervix is no longer the number one killer of women, reducing deaths from the disease by more than 70%. Yet Pap smear misreading is one of the more common reasons medical malpractice suits are filed against laboratories.
The tests’ vulnerability to criticism stems in part from the fact that Pap smears, unlike most other high-volume tests, are manual, subjecting them to human error and inexact judgments, and...