HPV Test and Cervical Screening: Pap Smear Guide

What Is HPV and Why Does It Cause Cervical Cancer?

Human papillomavirus (HPV) is the most common sexually transmitted infection globally, with over 200 types identified. High-risk HPV types, particularly HPV 16 and 18, cause nearly all cervical cancers by infecting cervical cells and, if the infection persists, causing cell changes that can progress to cancer over 10-20 years.

Human papillomavirus (HPV) is a group of more than 200 related viruses that infect the skin and mucous membranes. HPV is incredibly common, with approximately 80% of sexually active people acquiring at least one type of HPV at some point in their lives. The virus is spread through intimate skin-to-skin contact, primarily during vaginal, anal, or oral sex, but also through other intimate contact.

Most HPV infections are harmless and cause no symptoms. The body's immune system typically clears the infection within one to two years without the person ever knowing they were infected. However, when certain high-risk types of HPV persist in the body over many years, they can cause cell changes that may eventually lead to cancer. This process is typically slow, taking 10 to 20 years or more, which is why regular screening is so effective at catching and treating precancerous changes before they become cancer.

There are approximately 14 high-risk HPV types that can cause cancer, with HPV types 16 and 18 being the most dangerous, responsible for about 70% of all cervical cancer cases. Other high-risk types include HPV 31, 33, 45, 52, and 58. Low-risk HPV types, such as HPV 6 and 11, can cause genital warts but do not lead to cancer.

How HPV Leads to Cervical Cancer

When high-risk HPV infects the cells of the cervix (the lower part of the uterus that connects to the vagina), the virus inserts its genetic material into the host cells. In most cases, the immune system recognizes and eliminates these infected cells. However, when the infection persists, the viral proteins can interfere with the cell's normal growth controls, particularly proteins called E6 and E7 that inactivate tumor suppressor genes.

Over time, this interference causes the cervical cells to grow abnormally, creating what are called precancerous lesions or cervical intraepithelial neoplasia (CIN). These lesions are graded by severity: CIN 1 (mild changes, often regress on their own), CIN 2 (moderate changes), and CIN 3 (severe changes, also called carcinoma in situ). Without treatment, CIN 2 and CIN 3 lesions can progress to invasive cervical cancer, though this typically takes many years.

This slow progression from infection to cancer is precisely why cervical screening is so effective. By detecting HPV infection or precancerous changes early, healthcare providers can monitor the condition and intervene with treatment if necessary, preventing cancer from ever developing.

Risk Factors for Persistent HPV Infection

While anyone who is sexually active can contract HPV, certain factors increase the risk of the infection persisting and potentially leading to cervical cancer:

• Smoking: Tobacco use weakens the immune system's ability to clear HPV and damages cervical cells
• Weakened immune system: Conditions like HIV infection or immunosuppressive medications reduce the body's ability to fight HPV
• Long-term oral contraceptive use: Using birth control pills for more than 5 years may slightly increase risk
• Multiple sexual partners: Increases the chance of exposure to different HPV types
• Early sexual activity: Beginning sexual activity at a young age increases lifetime HPV exposure
• Other sexually transmitted infections: Chlamydia and other STIs may increase susceptibility

What Are the Different Types of Cervical Screening Tests?

There are three main cervical screening options: the Pap smear (cytology) that examines cells for abnormalities, the HPV test that detects high-risk virus DNA/RNA, and co-testing that combines both methods. HPV primary testing is increasingly recommended as the most sensitive screening method for detecting cervical cancer risk.

Cervical cancer screening has evolved significantly over the past decades. While the Pap smear was the standard screening method for over 50 years, the development of HPV testing has transformed how we approach cervical cancer prevention. Today, healthcare providers may offer several testing options depending on your age, health history, and local guidelines.

The Pap Smear (Cervical Cytology)

The Pap smear, named after Dr. George Papanicolaou who developed it in the 1940s, involves collecting cells from the cervix and examining them under a microscope for abnormalities. This test has been remarkably successful in reducing cervical cancer rates in countries that have implemented widespread screening programs. The Pap smear can detect abnormal cells at various stages, from minor changes (atypical squamous cells) to precancerous lesions and cancer cells.

During the test, a healthcare provider collects cells from the surface of the cervix using a soft brush or spatula. These cells are then either placed on a glass slide (conventional Pap smear) or preserved in a liquid medium (liquid-based cytology) for examination by a cytologist or pathologist. Liquid-based cytology has become the preferred method in many settings because it provides cleaner samples and allows for HPV testing from the same sample if needed.

The HPV Test

The HPV test detects the presence of high-risk HPV types in cervical cells, identifying the underlying cause of most cervical cancers rather than the cell changes themselves. Modern HPV tests typically look for DNA or RNA from 13-14 high-risk HPV types, with some tests specifically identifying HPV 16 and 18 (the highest-risk types) separately from other high-risk types.

Research has shown that HPV testing is more sensitive than the Pap smear alone in detecting precancerous lesions. This means HPV testing catches more cases of significant cell changes, though it may also detect infections that would have cleared on their own. Because of its high sensitivity, a negative HPV test provides strong reassurance that cervical cancer is unlikely to develop in the near future, allowing for longer intervals between screening tests.

Co-Testing (Pap Smear Plus HPV Test)

Co-testing combines both the Pap smear and HPV test, providing information about both the presence of HPV and any current cell changes. This combination offers the highest sensitivity for detecting precancerous lesions. Many guidelines recommend co-testing as an option for women aged 30 and older, as younger women frequently have transient HPV infections that clear naturally.

HPV Primary Screening

Increasingly, health organizations are recommending HPV testing alone (without concurrent Pap smear) as the primary screening method for women 25 or 30 years and older. This approach is based on strong evidence that HPV testing is more effective at detecting significant precancerous changes. When the HPV test is positive, follow-up may include a Pap smear (reflex cytology) to determine the next steps.

When Should You Get Screened for Cervical Cancer?

Cervical screening typically begins at age 21-25 and continues until age 65-70, with intervals depending on the test type: every 3 years for Pap smears alone, or every 5 years for HPV testing or co-testing. Women over 65 with adequate prior negative results can stop screening, while those with certain risk factors may need more frequent testing.

Cervical cancer screening recommendations have evolved based on decades of research showing what works best to prevent cancer while minimizing unnecessary procedures. The current guidelines balance the benefits of early detection against the potential harms of over-testing, such as anxiety from false positives and unnecessary treatments for abnormalities that would have resolved on their own.

Screening guidelines vary somewhat between countries and organizations, but they share common principles based on our understanding of how HPV infections progress. Here are the general recommendations followed by major health organizations including the World Health Organization (WHO), American College of Obstetricians and Gynecologists (ACOG), and the United States Preventive Services Task Force (USPSTF):

Ages 21-24: Starting Screening

Most guidelines recommend beginning cervical screening at age 21, regardless of when sexual activity began. Some countries start screening at age 25. For women in this age group, only Pap smears (not HPV tests) are typically recommended because HPV infections are very common in young women and usually clear on their own. Testing for HPV in this age group would lead to many positive results for infections that would never cause cancer, potentially resulting in unnecessary anxiety and procedures.

Ages 25-29: Pap Smears Every 3 Years

For women in their late twenties, screening continues with Pap smears every three years if results are normal. HPV testing may be done if a Pap smear shows certain abnormalities. Some countries now offer HPV testing as primary screening starting at age 25.

Ages 30-65: Multiple Options

Women aged 30 to 65 have several screening options, all considered acceptable by major guidelines:

• HPV test alone every 5 years (increasingly preferred)
• Co-testing (Pap smear + HPV test) every 5 years
• Pap smear alone every 3 years

The longer intervals with HPV testing are possible because a negative HPV test provides strong assurance that cervical cancer is unlikely to develop in the next several years. The virus must be present for a prolonged period before cell changes occur, so screening every five years still catches precancerous changes in time for effective treatment.

Age 65 and Older: When to Stop Screening

Women who have had adequate prior screening with normal results can generally stop cervical screening at age 65. "Adequate prior screening" typically means having three consecutive negative Pap smears or two consecutive negative HPV tests within the past 10 years, with the most recent test within the past 5 years.

Women who have been treated for precancerous lesions (CIN 2 or higher) should continue screening for at least 25 years after treatment, even if this extends past age 65, because they remain at higher risk for cervical cancer.

Special Circumstances

Some women may need different screening schedules:

• After hysterectomy: Women who have had a total hysterectomy (including removal of the cervix) for non-cancerous reasons and have no history of high-grade precancerous lesions do not need cervical screening
• HIV-positive women: Should be screened more frequently, typically annually
• Immunocompromised women: May need more frequent screening depending on their condition
• Women exposed to DES (diethylstilbestrol) in utero: May need continued annual screening

How Should You Prepare for a Cervical Screening Test?

To prepare for cervical screening, avoid vaginal intercourse, douching, and vaginal products for 48 hours before your appointment. Schedule the test for a time when you are not menstruating (ideally mid-cycle). You can shower or bathe normally and empty your bladder before the exam for comfort.

Proper preparation for your cervical screening appointment helps ensure accurate results and a more comfortable experience. While the test itself takes only a few minutes, taking some simple steps beforehand can make a difference in the quality of your sample and your overall comfort during the procedure.

The main goal of preparation is to avoid anything that might interfere with the collection of cervical cells or affect the accuracy of the test results. Here are the key recommendations for the 48 hours before your appointment:

What to Avoid Before Your Test

• Vaginal intercourse: Sexual activity can disturb cervical cells and introduce substances that may affect test results
• Douching: This can wash away cells needed for the test and alter the normal vaginal environment
• Vaginal medications: Including creams, suppositories, and lubricants (unless medically necessary)
• Spermicides: These can interfere with test accuracy
• Tampons: Avoid using tampons for 24-48 hours before the test

Timing Your Appointment

The best time for cervical screening is when you are not menstruating. Blood and menstrual tissue can affect the quality of the cell sample and make it harder to interpret results. The ideal time is typically mid-cycle, about 10-20 days after the first day of your last menstrual period. However, if you have irregular periods or your appointment falls during an unexpected period, contact your healthcare provider to discuss whether to reschedule.

Light spotting may not necessarily require rescheduling, but heavy bleeding usually does. Your healthcare provider can advise you based on your specific situation.

On the Day of Your Appointment

You can shower or bathe normally before your appointment. Emptying your bladder before the examination can make you more comfortable during the procedure, as a full bladder can create pressure against the uterus. Wear comfortable clothing that is easy to remove from the waist down, as you will need to undress for the examination.

If you feel nervous about the procedure, it can be helpful to practice relaxation techniques such as deep breathing. You might also want to bring a supportive friend or family member to your appointment. Many women find that talking with their healthcare provider about their concerns helps reduce anxiety.

What Happens During a Cervical Screening Test?

During cervical screening, you lie on an examination table while a healthcare provider inserts a speculum to visualize the cervix, then gently collects cells using a soft brush or spatula. The entire procedure takes 3-5 minutes and should not be painful, though some women experience mild discomfort or pressure.

Understanding what to expect during a cervical screening test can help reduce anxiety and make the experience more comfortable. While many women feel nervous about pelvic examinations, knowing the steps involved often helps people feel more prepared and in control.

Before the Collection

When you arrive for your appointment, you may be asked to provide a urine sample and answer questions about your menstrual cycle, contraception use, and any symptoms you may be experiencing. You will then be shown to an examination room where you will undress from the waist down and be given a drape or gown for privacy. The healthcare provider will explain the procedure and answer any questions before beginning.

Positioning for the Examination

You will lie on your back on an examination table with your knees bent and feet placed in stirrups or on foot rests. Some examination tables have padded stirrups or allow you to place your feet flat on the table with knees bent. Your healthcare provider will ensure you are positioned comfortably before proceeding.

The Cell Collection Process

The healthcare provider will first visually examine the external genital area. Then, they will gently insert a speculum into the vagina. A speculum is a medical instrument that holds the vaginal walls apart, allowing the provider to see the cervix clearly. The speculum may feel cool when first inserted and you will feel some pressure, but it should not be painful. If you experience discomfort, let your provider know they can adjust the speculum or try a different size.

Once the cervix is visible, the provider will use a soft brush (cytobrush) or spatula to gently collect cells from the surface of the cervix and the opening of the cervical canal. This collection process takes only a few seconds. You may feel a slight scraping sensation, which some women describe as mildly uncomfortable but not painful. The cells are then either placed in a preservative liquid (for liquid-based cytology) or spread on a glass slide.

After the Collection

Once the sample is collected, the speculum is gently removed. The entire examination typically takes only 3-5 minutes. You can get dressed immediately afterward and resume all normal activities. Some women experience light spotting after the test, which is normal and usually stops within a day or two.

HPV Self-Collection

An emerging option in some healthcare settings is HPV self-collection, where you collect your own vaginal sample using a swab at home or in a private space at a clinic. Research has shown that self-collected samples are nearly as accurate as provider-collected samples for HPV testing. Self-collection may be particularly helpful for women who find pelvic examinations difficult due to anxiety, physical disability, or past trauma, or for those who face barriers to accessing healthcare.

What Do Your Cervical Screening Results Mean?

Normal results mean no abnormalities were found and routine screening continues. Abnormal Pap smear results range from ASC-US (minor changes, often resolve naturally) to HSIL (high-grade changes requiring treatment). A positive HPV test indicates the virus is present, requiring follow-up testing to check for cell changes.

Receiving your cervical screening results can be an anxious time, especially if you receive notice of an abnormal finding. Understanding what different results mean can help you have informed discussions with your healthcare provider about next steps. It's important to remember that most abnormal results do not mean you have cancer, and many abnormalities resolve on their own or can be easily treated.

Results typically take one to three weeks to come back, depending on your healthcare system. You should receive notification of your results either by mail, through an online patient portal, or via a phone call from your healthcare provider's office. If you haven't received results within the expected timeframe, contact your provider to follow up.

Normal (Negative) Results

Normal Pap smear: No abnormal cells were found. You can continue with routine screening at the recommended interval for your age.

Negative HPV test: No high-risk HPV types were detected. This provides strong reassurance that cervical cancer is unlikely to develop in the near future, and you can typically wait five years before your next screening test.

Abnormal Pap Smear Results

Abnormal Pap smear results are classified using the Bethesda System, which describes the type and severity of cell changes found:

ASC-US (Atypical Squamous Cells of Undetermined Significance): This is the most common abnormal result and indicates minor cell changes that could be due to HPV infection, inflammation, or other benign causes. Most ASC-US findings resolve on their own. Follow-up typically involves HPV testing (if not already done); if HPV-negative, routine screening continues; if HPV-positive (especially for types 16/18), colposcopy may be recommended.

LSIL (Low-grade Squamous Intraepithelial Lesion): Indicates mild cell changes, usually caused by HPV infection. Most LSIL findings resolve without treatment within one to two years. Depending on age and other factors, follow-up may include repeat testing in one year or colposcopy.

ASC-H (Atypical Squamous Cells, cannot exclude HSIL): Cell changes are present that might indicate a more significant abnormality. Colposcopy is typically recommended to examine the cervix more closely.

HSIL (High-grade Squamous Intraepithelial Lesion): Indicates more significant cell changes that are more likely to progress to cancer if left untreated. Colposcopy with biopsy is recommended, and treatment is usually necessary.

AGC (Atypical Glandular Cells): Abnormal cells from the glandular tissue of the cervix or uterus. This finding requires further evaluation with colposcopy and possibly additional testing.

Positive HPV Test Results

A positive HPV test means that high-risk HPV was detected in your sample. This does not mean you have cancer or even precancerous changes, only that the virus is present. Most HPV infections clear on their own without causing any problems.

Follow-up for a positive HPV test depends on several factors, including your age, whether specific HPV types (16 or 18) were detected, and your Pap smear results if co-testing was done. Your healthcare provider will guide you on next steps, which may include:

• Repeat testing in one year (if HPV-positive but Pap smear normal and HPV 16/18 not detected)
• Colposcopy (if HPV 16 or 18 detected, or if Pap smear shows abnormalities)
• More frequent monitoring

What Happens If You Need a Colposcopy?

Colposcopy is an examination where a healthcare provider uses a magnifying device (colposcope) to closely examine the cervix for abnormal areas after an abnormal screening result. During the procedure, a vinegar solution is applied to highlight abnormal cells, and biopsies may be taken from suspicious areas for laboratory analysis.

If your cervical screening results indicate the need for further evaluation, your healthcare provider may recommend a colposcopy. This procedure allows for a detailed examination of the cervix that isn't possible with the naked eye, helping to determine whether abnormal cells are present and how severe they might be.

A colposcopy is typically recommended when Pap smear results show HSIL, ASC-H, or persistent LSIL; when HPV types 16 or 18 are detected; when there are repeated abnormal results; or when there are visible cervical abnormalities during routine examination. Having a colposcopy does not mean you have cancer. It's a diagnostic tool to better understand what's happening with your cervical cells.

The Colposcopy Procedure

A colposcopy is performed in a clinic or doctor's office and typically takes 15-20 minutes. The positioning is similar to a Pap smear, with you lying on an examination table with feet in stirrups. A speculum is inserted to visualize the cervix, and the colposcope (a magnifying instrument with a light, similar to binoculars on a stand) is positioned outside your body to examine your cervix.

The provider will apply a dilute vinegar (acetic acid) solution to the cervix. This solution causes abnormal cells to turn white temporarily, making them easier to identify against the normal pink cervical tissue. A second solution (Lugol's iodine) may also be applied; normal cells stain brown while abnormal cells remain unstained.

If abnormal areas are identified, the provider may take small tissue samples (biopsies) for laboratory analysis. You will feel a brief pinch or cramping sensation during the biopsy. Some providers use a local anesthetic to numb the area first, especially if multiple biopsies are needed.

After the Colposcopy

You may experience light spotting or a dark discharge (from the iodine solution) for a few days after the procedure. If biopsies were taken, you should avoid vaginal intercourse, tampons, and douching for several days to allow healing. Most women can return to normal activities immediately.

Biopsy results typically take one to two weeks. Your healthcare provider will contact you to discuss the findings and any recommended treatment or follow-up.

How Are Abnormal Cervical Cells Treated?

Treatment for abnormal cervical cells depends on the severity of changes. Low-grade changes (CIN 1) are often monitored without treatment. High-grade changes (CIN 2/3) are typically treated with procedures like LEEP (loop electrosurgical excision), cryotherapy, laser therapy, or cone biopsy to remove the abnormal tissue while preserving fertility.

When colposcopy and biopsy confirm precancerous cervical changes, your healthcare provider will recommend a management approach based on the severity of the changes, your age, your desire for future pregnancy, and other health factors. The goal of treatment is to remove or destroy the abnormal cells before they can develop into cancer while preserving as much healthy cervical tissue as possible.

Watchful Waiting (Active Surveillance)

For low-grade changes (CIN 1), treatment is often not immediately necessary because many of these changes regress on their own, especially in younger women. Your provider may recommend "watchful waiting" with repeat testing (Pap smear and/or HPV test) in one year. If the abnormality persists for two years or progresses, treatment may then be recommended.

Excisional Treatments

These procedures physically remove the abnormal tissue, providing a sample that can be examined in the laboratory to ensure all abnormal cells have been removed:

LEEP (Loop Electrosurgical Excision Procedure): The most common treatment, LEEP uses a thin wire loop carrying an electrical current to remove the abnormal tissue. It's performed in the office under local anesthesia and takes about 10-20 minutes. Recovery involves avoiding strenuous activity, sexual intercourse, and tampons for several weeks.

Cone Biopsy (Conization): A cone-shaped piece of tissue is removed from the cervix, including the transformation zone where most abnormalities occur. This can be done with a scalpel (cold knife cone), laser, or LEEP. Cone biopsy removes more tissue than LEEP and may be recommended for more extensive abnormalities or when glandular cells are involved.

Ablative Treatments

These treatments destroy abnormal tissue without removing it. They are an option when the abnormality is clearly visible and limited in extent:

Cryotherapy: Uses extreme cold (liquid nitrogen or carbon dioxide) to freeze and destroy abnormal cells. This is a simple, inexpensive procedure often used in resource-limited settings.

Laser Ablation: Uses a laser beam to vaporize abnormal tissue. This allows precise treatment but requires specialized equipment.

Follow-Up After Treatment

After treatment for precancerous changes, you will need more frequent monitoring than the general population because the risk of developing cervical cancer or recurrence of precancerous changes remains elevated for many years. Current guidelines recommend surveillance with Pap smears and/or HPV testing at regular intervals for at least 25 years after treatment, even if this extends past age 65.

How Can You Prevent Cervical Cancer?

Cervical cancer is highly preventable through HPV vaccination (over 90% effective when given before HPV exposure), regular cervical screening to detect and treat precancerous changes, practicing safe sex, not smoking, and maintaining a healthy immune system. Combining vaccination with screening provides the best protection.

Cervical cancer is one of the most preventable cancers due to our understanding of its cause (HPV infection) and the availability of effective tools for prevention and early detection. A comprehensive approach combining primary prevention (avoiding infection) and secondary prevention (detecting and treating precancerous changes) can virtually eliminate cervical cancer.

HPV Vaccination

The HPV vaccine is one of the most important advances in cancer prevention. Current vaccines protect against the HPV types that cause the majority of cervical cancers (types 16 and 18) as well as types that cause genital warts (types 6 and 11) and other HPV-related cancers. The 9-valent vaccine (Gardasil 9) protects against nine HPV types that together cause about 90% of cervical cancers.

The vaccine is most effective when given before any exposure to HPV, which is why it's recommended for boys and girls starting at age 11-12, though it can be given as early as age 9. Catch-up vaccination is recommended through age 26 for those not previously vaccinated, and some guidelines allow vaccination up to age 45 for individuals who may still benefit.

Studies from countries with high vaccination rates have already shown dramatic reductions in HPV infections, genital warts, and precancerous cervical changes among vaccinated populations. As vaccinated generations age, we expect to see significant declines in cervical cancer rates.

Regular Cervical Screening

Even with vaccination, regular cervical screening remains essential. The vaccine does not protect against all cancer-causing HPV types, and people who were exposed to HPV before vaccination are not protected against those strains. Screening detects any precancerous changes that do develop, allowing for treatment before cancer occurs.

Lifestyle Factors

Several lifestyle factors can reduce your risk of persistent HPV infection and cervical cancer:

• Don't smoke: Smoking significantly increases the risk of cervical cancer and reduces the body's ability to clear HPV infections
• Practice safe sex: While condoms don't completely prevent HPV transmission (as HPV can infect areas not covered by condoms), they do reduce the risk and protect against other sexually transmitted infections
• Limit sexual partners: Having fewer partners reduces your overall exposure to different HPV types
• Maintain a healthy immune system: A strong immune system is better able to clear HPV infections naturally