In gynecology, the Papanikolaou test (also called Pap smear, Pap test, cervical smear, or smear test) is a medical screening method for detecting infectious, premalignant, and malignant processes in the ectocervix, endocervix and endometrium.
The pre-cancerous changes (called dysplasias or cervical or endocervical intraepithelial neoplasia) are usually caused by sexually-transmitted human papillomaviruses (HPVs). The test aims to detect and prevent the progression of HPV-induced cervical cancer and other abnormalities in the female genital tract by sampling cells from the outer opening of the cervix (latin for "neck") of the uterus and the endocervix. The sampling technique changed very little since its invention by Georgios Papanikolaou (1883-1962) to detect cyclic hormonal changes in vaginal cells in the early 20th century until the development of liquid based cell monolayer technology. The test remains a highly-effective, widely used method for early detection of cervical cancer and pre-cancer.
It is generally recommended that sexually active women seek Pap smear testing annually, although guidelines may vary from country to country. If results are abnormal, and depending on the nature of the abnormality, the test may need to be repeated in three to twelve months. If the abnormality requires closer scrutiny, the patient may be referred for detailed inspection of the cervix by colposcopy. The patient may also be referred for HPV DNA testing, which can serve as an adjunct (or even as an alternative) to Pap testing.
About 5% to 7% of pap smears produce abnormal results, such as dysplasia, possibly indicating a pre-cancerous condition. Although many low grade cervical dysplasias spontaneously regress without ever leading to cervical cancer, dysplasia can serve as an indication that increased vigilance is needed.
Endocervical and endometrial abnormalities can also be detected, as can a number of infectious processes, including yeast and trichomonas. A small proportion of abnormalities are reported as of "uncertain significance".
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