Risks
By Mayo Clinic staffA Pap smear is a safe way to screen for cervical cancer. However, a Pap smear isn't foolproof. It's possible to receive false-negative results — meaning that the test indicates no abnormality, even though you do have abnormal cells.
A false-negative result doesn't mean that a mistake was made. Factors that can cause a false-negative result include:
- An inadequate collection of cells
- A small number of abnormal cells
- Blood or inflammatory cells obscuring the abnormal cells
Although it's possible for abnormal cells to go undetected, time is on your side. Cervical cancer takes several years to develop. And if one test doesn't detect the abnormal cells, the next test most likely will.
- The Pap test. American Congress of Obstetricians and Gynecologists. http://www.acog.org/publications/patient_education/bp085.cfm. March 17, 2010.
- Pap test. WomensHealth.gov. http://www.womenshealth.gov/faq/pap-test.cfm. Accessed March 17, 2010.
- Cervical cytology screening. American Congress of Obstetricians and Gynecologists. Obstetrics & Gynecology. 2009;114:1409.
- Smith RA, et al. Cancer screening in the United States, 2010: A review of current American Cancer Society guidelines and issues in cancer screening. CA: A Cancer Journal for Clinicians. 2010;60:99.
- Screening for cervical cancer. U.S. Preventive Services Task Force. http://www.ahrq.gov/clinic/3rduspstf/cervcan/cervcanrr.htm. Accessed March 17, 2010.
- Sirovich BE, et al. Screening for cervical cancer. http://www.uptodate.com. Accessed March 17, 2010.
- Cervical cancer screening. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/PDF/cervical_screening.pdf. Accessed March 17, 2010.
- Gallenberg MM (expert opinion). Mayo Clinic, Rochester, Minn. March 18, 2010.

Find Mayo Clinic on