A Pap smear does not test for Chlamydia, although both procedures are frequently performed during the same examination. The Pap test screens for cervical cancer by analyzing cell changes, while the Chlamydia test is a separate diagnostic procedure that looks for the presence of a specific bacterium. Even when a single sample is collected, it is divided and processed using two entirely different laboratory methods. This co-collection during a single office visit is the primary source of patient confusion regarding the purpose of each test.
The Purpose of a Pap Smear
The primary function of a Pap smear is to screen for precancerous and cancerous changes in the cells of the cervix. This test is a form of cervical cytology, where collected cells are examined microscopically for abnormalities, such as dysplasia. Detecting these cellular changes early allows for intervention before they progress into invasive cervical cancer, making the Pap smear a highly effective cancer prevention tool.
The test is frequently paired with screening for Human Papillomavirus (HPV), a common sexually transmitted infection. Persistent infection with high-risk types of HPV causes nearly all cervical cancers. This combined procedure is often called co-testing, where the HPV test analyzes the sample for the virus’s genetic material. While the Pap test can reveal general inflammation, its specific purpose is identifying abnormal cell growth related to cancer risk.
The Separate Test for Chlamydia
The test for Chlamydia is fundamentally different from a Pap smear because it looks for a bacterial infection, not abnormal cell structure. Chlamydia is caused by the bacterium Chlamydia trachomatis and is one of the most common sexually transmitted infections. If left untreated, it can lead to serious health complications like pelvic inflammatory disease and infertility.
The standard for Chlamydia screening is Nucleic Acid Amplification Testing (NAAT). This method works by detecting the specific genetic material (DNA or RNA) of the Chlamydia trachomatis bacterium present in a sample. The specimen is typically a swab collected from the cervix or vagina, or sometimes a urine sample. The laboratory analysis focuses entirely on bacterial DNA, not the microscopic appearance of human cells.
Why Screening Tests Are Often Combined
Combined sample collection during a single pelvic exam is why many people mistakenly believe the Pap smear includes Chlamydia screening. During the exam, a healthcare provider collects cells for the Pap and HPV tests, and then uses a separate device to gather a sample for Chlamydia and Gonorrhea testing. The physical process of collecting both specimens occurs within the same few minutes, making the screening process more efficient for the patient.
This procedural overlap does not mean the tests are the same. The collected samples are sent to the lab for distinct analyses: cytology for the Pap smear and NAAT for bacterial screening. Patients should always confirm with their provider exactly which tests have been ordered, as combined collection depends on individual age and risk factors.