Pap test or pap smear. Why it's done A Pap smear is used to screen for cervical cancer. The Pap smear is usually done in conjunction with a pelvic exam. In women older than age 30, the Pap test may be combined with a test for human papillomavirus (HPV) — a common sexually transmitted infection that can cause cervical cancer. In some cases, the HPV test may be done instead of a Pap smear. Who should have a Pap smear? You and your doctor can decide when it's time for you to begin Pap testing and h