Traditionally, genital HPV infection has been detected as abnormal cell changes on a Pap smear, a test used primarily to detect cancer of the cervix (the lower part of the uterus or womb) or conditions that may lead to cancer. During a Pap smear, the appearance of cervical cells is evaluated under a microscope. Certain changes in the cells may indicate an HPV infection, but there is no clear distinction between high- and low-risk types.
DNA testing for HPV can be used as a follow-up to abnormal changes detected with a Pap smear. Guidelines from several organizations now recommend that HPV DNA tests be ordered along with a Pap smear for women 30 to 65 years of age. There are several DNA HPV tests, some approved for marketing by the FDA, that can detect high-risk types of HPV.
The American College of Obstetricians and Gynecologists (ACOG), the U.S. Preventive Services Task Force (USPSTF), and the American Cancer Society (ACS) now recommend HPV testing as part of routine cervical cancer screening for women 30 to 65 years of age, along with Pap smears, every 5 years.
The HPV DNA test is not recommended for screening women younger than age 30 because infections with HPV are relatively common in this age group and often resolve without treatment or complications. However, it may be used as a follow-up test in women who are 21 years or older who have abnormal results on a Pap smear known as "atypical squamous cells of undetermined significance" (ASCUS) [see Pap Smear Terminology]. Results may be used to determine the need for colposcopy, a procedure that allows a doctor to visually inspect the vagina and cervix under magnification for the presence of abnormal cells.
Some doctors will test men who fall into a high-risk category. Men who have sex with men and those who have HIV may be tested for HPV. Evaluating the risk of HPV-related diseases of the anal canal in men is becoming more common.
On a Pap smear, ASCUS and low-grade changes indicate the likely presence of HPV and the need for further testing. A positive HPV DNA test indicates the presence of a high-risk type of HPV, but the test does not specify which type is present. If the HPV DNA test is negative, it is unlikely that there is a high-risk HPV infection. If the Pap smear is abnormal but the HPV DNA test is negative, then follow-up testing and further monitoring are indicated. The Centers for Disease Control and Prevention says to wait three years before getting another Pap smear and HPV test and to talk to the doctor about when to come in for another visit. Likewise, if the Pap smear is normal but the HPV DNA test is positive, additional testing may be necessary. It is recommended to have another Pap smear and HPV test in one year, at which point the Pap smear will indicate if any cell changes have occurred during that time.
The tests most commonly used to screen for HPV only detect those types that have a higher risk of progressing to cancer. If positive, they indicate the presence of one of these high-risk types:
Sometimes, molecular tests to detect and identify low-risk HPV types are ordered. If the result is positive, it indicates the presence of one of the low-risk types:
HPV types 6 and 11 (which typically cause venereal warts), 42, 43, and 44.
A test approved by the FDA in 2009 identifies the specific HPV subtypes 16 and 18. If this test is positive, it indicates the presence of subtypes that cause 70% of cervical cancer. A second DNA test, also approved in 2009, detects essentially all of the high-risk HPV types in cervical cell samples.
A doctor might take a small piece of tissue (a biopsy) from the cervix and examine it under a microscope. When either the Pap smear or the biopsy indicates a condition that could lead to cancer (called intraepithelial neoplasia), an HPV DNA test can determine if the patient is infected with a high-risk strain of HPV that increases the chance that cancer might develop if not treated.
Some doctors test men who are at high risk for sexually transmitted diseases for HPV-related anal cancer. Such testing is similar to a cervical Pap smear. The anal lining is swabbed and the cells are examined under a microscope. HPV DNA tests can also be performed on these samples. As in cervical samples, positive results will need to be followed up by the doctor with further testing, including a more thorough exam and possible biopsy.
Although very rare, a pregnant woman may pass HPV to her baby during vaginal delivery, resulting in warts in the throat or voice box (laryngeal papillomatosis or recurrent respiratory papillomatosis, RRP).
This article was last reviewed on June 13, 2012. | This article was last modified on February 12, 2015.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
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