Screening tests are tests performed on people without symptoms to find hidden indicators of disease. Screening tests that show abnormal results must be followed up with diagnostic tests. A Pap smear is a screening test that checks for abnormal changes in your cervix's cells. These abnormal cells can sometimes turn into cancerous cells. Your cervix is the lower part of your uterus (womb), which opens into your vagina. The Pap test is done during a pelvic exam. Your doctor uses a swab to collect a sample of cells from your cervix. The cells are sent to a laboratory to check for abnormalities.

It could save your life. About 13,000 American women are diagnosed with cervical cancer each year and nearly 5,000 die of this disease. Most cervical cancers begin as lesions that develop into cancer gradually over time. Regular Pap tests can detect abnormal changes before they become cancerous. All women who are over 18, or who are sexually active, should have Pap smears at least once every three years. This also applies to women who are no longer sexually active, or who are post-menopausal. In fact, it's very important for older women to continue having Pap tests. Twenty-five percent of cervical cancers are diagnosed in women over age 65; and women over age 65 account for 41 percent of cervical cancer deaths. Getting regular Pap tests is especially important for Asian, Hispanic and African-American women, because they are more likely to die from cervical cancer.

No. Sometimes the test shows no abnormal cells when there are actually a few. This is called a false negative. This can happen when the abnormal cells aren't in the sample your doctor takes from your cervix, or when there aren't enough cells to test. False negatives can also happen if you have an infection that covers up abnormal cells.

But regular screening reduces the problem of false negatives. If one test misses some abnormal cells, the next test will likely find it before it has grown into cancer. Most women diagnosed with invasive cervical cancer have not had regular Pap smears.

Several factors can increase your risk of getting cervical cancer. The biggest risk factor is infection with certain strains of human papillomavirus (HPV) - a virus that can cause genital warts. There are more than 80 different kinds of HPV; about 30 are spread through sexual contact. About half of these strains of HPV are linked with cervical cancer, but these few strains are found in over 90 percent of cervical cancers. Age is also a risk factor - the chance of dying of cervical cancer increases as women get older. Other risk factors include smoking, having sex in your early teens, having many sexual partners, and not having regular Pap tests.

Yes. To prevent HPV, practice safe sex by using condoms and limit your number of sexual partners. Quitting smoking will also reduce your risk. Eating healthy foods and staying active can help protect against many forms of cancer. Most important, make sure you have a gynecological exam and Pap test every year or at least once every three years.

Schedule an appointment with your gynecologist. Pick a day when you won't have your period. Do not douche for at least three days before your appointment. Don't have sex for 24 to 48 hours before your appointment. Don't use tampons, birth control foams or jellies for two days before your appointment. Shower instead of taking tub baths for two days before your appointment. Tell your doctor if you've been exposed to human papillomavirus (HPV).

If your cells look normal, then you don't have to do anything until your next regularly scheduled visit to your doctor. If your cells look abnormal, your doctor will want to do some more tests to find out why. You may need a test called colposcopy. In this test, which is done in the office, your doctor will use a large, electric microscope to take a closer look at your cervix and remove some tissue to send to the lab. Your doctor will also want you to follow up with more frequent Pap tests until you have three normal results in a row. Abnormal cells can be treated by freezing, by surgical removal or by destruction with a laser or electrical device.

To improve the accuracy of the Pap test a new liquid based test is being used. This test is collected in the same way but the cells are placed in liquid and the slides are made in the lab. This technique cuts down on false negatives and allows for other testing on the cells. If a minor abnormality is seen in the cells, they can be tested for HPV virus. If this test is negative, routine follow-up is suggested. If the test shows HPV virus, a colposcopy is done to determine if there are any pre-cancerous changes.