DIAGNOSTIC cytology was developed in the 1930s and 1940s by Dr George Papanicolaou.1,2 His early work in reproductive physiology in animals was extended to that of the human female in whom hormonal status was determined by observing cytological changes in the vaginal smear. After many years of examining normal human exfoliative cytological specimens, Papanicolaou applied the technique to the study of pathological conditions. This effort culminated in the publication of a monograph Diagnosis of Uterine Cancer by the Vaginal Smear in 1943.3
Interpretation of cells removed from the female genital tract and stained by the Papanicolaou method has resulted in the earlier diagnosis of carcinoma of the uterine cervix and its precursor lesions. The Papanicolaou (Pap) smear may also detect specific infections of the lower genital tract and malignancies at other sites in the genital tract, but its primary role has been in screening for cervical neoplasms.