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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• What is a Pap smear?
• Who should have a Pap smear?
• Which women are at increased risk for having an abnormal Pap smear?
• How is a Pap smear done?
• What are the risks of having a Pap smear?
• How is a Pap smear read (analyzed)?
• What information is included on a Pap smear report?
• Why is a woman's menstrual status important for the Pap smear?
• Why is a woman's past Pap smear history pertinent?
• When might a Pap smear not be adequate for interpretation?
• How is the final Pap smear diagnosis made?
• What are the possible recommendations for follow-up after a Pap smear?
• What treatments are available if a Pap smear is abnormal?
• What is the follow-up after treatment for an abnormal Pap smear?
• What is the current status of human papilloma virus (HPV) testing?
• When should women start and stop having Pap smears, and how often should Pap smears be performed?
• What is the current status of the newer Pap smear technologies?
• With Pap smears so available, why are women still dying of cervical cancer?
• Historical note: Dr. Pap
• Pap Smear At A Glance
• Patient Comments: Pap Smear - Results
• Patient Comments: Pap Smear - Testing
• Find a local Obstetrician-Gynecologist in your town
• Pap Smear Index

What are the risks of having a Pap smear?

There are absolutely no known medical risks associated with Pap smear screening. (However, there are medical risks from not having a Pap smear.)

How is a Pap smear read (analyzed)?

Pap smear analysis and reports are all based on a medical terminology system called The Bethesda System. The system was developed (at the National Institutes of Health (NIH) in Bethesda, Maryland) to encourage all medical professionals analyzing Pap smears to use the same reporting system. Standardization reduces the possibility that different laboratories might report different results for the same smear. Standardization and uniform terminology also make Pap smear reports less confusing for the clinicians who request the tests and for their women patients.

The Bethesda System was the outcome of a National Cancer Institute workshop that was held in 1988 in an effort to standardize Pap reports. The guidelines address many aspects of Pap smear testing and its results. In 2001, the guidelines were revised and improved. Acceptance of the Bethesda reporting system in the United States is virtually universal.

The major categories for abnormal Pap smears reported in the Bethesda Systems are as follows:

• ASC-US: This abbreviation stands for atypical squamous cells of undetermined significance. Under the old system of classification, this category was called atypical squamous cells, just ASC. The new system requires the reader to pick one of two choices to add at the end of ASC: ASC-US, which means undetermined significance or ASC-H, which means cannot exclude HSIL-see below.
  
  
• LSIL: This abbreviation stands for low-grade squamous intraepithelial lesion. Under the old system of classification, this category was called CIN grade I.
  
  
• HSIL: This abbreviation stands for high-grade squamous intraepithelial lesion. Under the old system of classification, this category was called CIN grade II, CIN grade III, or CIS.

The word "squamous" describes the thin, flat cells that lie on the surface of the cervix. "Intraepithelial" indicates that the surface layer of cells is affected. A "lesion" means that abnormal tissue is present. These important terms - LSIL and HSIL - are described in greater detail below.