PapanicolaouTest

The Papanicolaou test, also known as the Pap test or Pap smear, is a cytological screening procedure used to detect cervical cancer and precancerous changes. It is named after Georgios Papanikolaou, who developed the method in the 1940s. The test has been central to cervical cancer control and contributed to large reductions in mortality in countries with organized screening programs.

In the procedure, cells are gently collected from the cervix (and sometimes the vaginal canal) during a pelvic examination using a small brush or spatula. The collected cells are placed on a slide or mixed into a liquid medium (liquid-based cytology), then stained with the Papanicolaou stain. A trained cytotechnologist or cytopathologist examines the cells under a microscope and reports the findings using a standardized system.

Reporting uses systems such as the Bethesda System, with categories including negative for intraepithelial lesion or malignancy (NILM), and epithelial abnormalities (ASC-US, ASC-H, LSIL, HSIL), as well as unsatisfactory specimens. In many settings, Pap tests are performed together with human papillomavirus (HPV) testing, especially for women over 30.

Limitations include imperfect sensitivity and the possibility of false negatives; sampling errors and interpretation variability can affect results. A normal result does not guarantee absence of cervical disease, and abnormal results require follow-up with repeat testing, colposcopy, or treatment as indicated. Ongoing screening intervals depend on age and local guidelines and may range from every 3 years (Pap alone) to every 5 years (co-testing with HPV).