The Papanicolaou smear: its value and limitations

Although the Papanicolaou (Pap) smear is one of the most effective screening tests ever invented for a common cancer, it remains an imperfect test. The technical shortcomings of the Pap smear have been compounded by the general public's unrealistically high expectations of the test's accuracy, underestimations of the importance of regular smears, and the actions within the medico-legal system. To remedy some of the technical shortcomings, the Bethesda System, which better reflects our current knowledge about cervical neoplasia, has been proposed to replace the old Papanicolaou classification system. Although standardized cytologic criteria may reduce interobserver variability, the false-negative rate of Pap smears is at least 5%, even in the best laboratories. No amount of training or experience with human observers can reduce the error rate to zero. Automated Pap screening holds the promise of higher sensitivity, but no instruments to date have been approved as a sole means of primary screening. The family physician can play a unique role in overcoming the limitations of the Pap smear by educating patients about the value and limitations of the test, instituting patient-specific treatment or follow-up of abnormal smears based on clinical and cytologic findings, and encouraging patients to get regular smears at intervals based on risk.