Human papillomavirus (HPV) blood tests and Pap smear tests are methods for detecting cervical cancer. Doctors may recommend a person has both tests to check for cervical cancer.

Cervical cancer is preventable if doctors can identify it early. Effective cervical cancer screening allows doctors to detect the disease before it grows and spreads to other areas.

Cervical cancer is the fourth most common cancer in women. Almost all of these cases link to persistent infections with high-risk HPV. Cervical cancer screening includes an HPV test, a Pap smear, or both.

This article explores HPV and Pap smear tests for detecting cervical cancer.

Cervical cytology, also known as a Pap test or Pap smear, is the gold standard for screening cervical cancer. The test looks for precancers, or abnormal cell changes, in the cervix. These may evolve into cancer without the correct treatment.

HPVs are a large group of viruses. HPV is the most widespread sexually transmitted infection in the United States.

The type of HPV that causes genital warts is not the same virus that causes cancers. Most HPV types are skin HPVs, which cause common warts. On the other hand, mucosal HPVs target and live on mucosal surfaces.

Mucosal cells line body parts that open to the outside, such as the vagina and anus. Doctors may also refer to mucosal types of HPV as genital HPV because they typically infect these areas.

Genital HPV can be low risk, which causes genital warts but rarely causes cancer. Or it may be high risk, meaning it is more likely to cause cancer.

A person can get HPV through skin-to-skin contact. A person who has vaginal, anal, or oral sex with someone who has the virus can contract HPV.

HPV can cause genital warts and certain cancers. These include:

The American Cancer Society (ACS) states that HPV does not spread through blood or bodily fluids such as semen. There is no blood, urine, anal, or oral swab that can detect HPV.

The only way to detect HPV is by viewing cell samples from the cervix under a microscope. This is because the virus passes through skin-to-skin contact and infects the skin and mucosal cells.

But a 2019 animal study discovered that HPV could cause infections through blood.

In addition, a 2020 study found a pinprick blood test to be effective in the early detection of antibodies for HPV 16. This type of HPV is responsible for most HPV-related head and neck cancers and 70% of cervical cancers.

Since HPV is a widespread viral infection, many people who are sexually active are likely to be infected at some point in their lives. The body’s immune system often clears the virus within a few months to 2 years.

Some HPV types may linger. A persistent, long-lasting, untreated HPV infection may turn normal cells into abnormal ones, which doctors call precancerous cells.

Without detection, these cells will continue to grow and multiply, causing cancer. But it typically takes 10–20 years or more before precancerous cells develop into a tumor.

Pap smears detect abnormal cells, which can be precancerous or cancerous. On the other hand, an HPV test checks for the DNA or RNA of cells to see if people have a high-risk HPV infection that can cause cervical cancer.

Should they be used together?

Doctors may use Pap smears and HPV tests to screen for cervical cancer.

In their 2020 guidelines on cervical cancer screening, the ACS recommends that people with a cervix get a primary HPV test every 5 years between ages 25–65 years. It also recommends an HPV/Pap co-test every 5 years, or Pap test alone every 3 years if HPV testing alone is unavailable.

What to expect during each test

Doctors usually do both tests during a pelvic exam. During this, a person lies on an exam table, bending their knees and using the surface to support their feet.

The doctor inserts a plastic or metal device in the vagina to widen it and provide a clear view of the upper vagina and cervix.

The doctor then uses a brush to collect cell and mucus samples from the cervix, places them in a special fluid, and sends them to a lab for analysis.

Doctors may use the same sample for both tests.

Labs usually release results within 1–3 weeks. If they find something abnormal in the results, a doctor will contact the person to discuss their test results.

The doctor will talk about the person’s risk and the next course of action. Pap smear results can be:

  • Normal: No abnormal cell changes in the cervix.
  • Unclear: Cervical cells could be abnormal, but it is unclear whether this relates to HPV. An unclear result can be due to pregnancy, an infection, or menopause.
  • Abnormal: There are cervical changes. This is likely the result of HPV and can be low grade or high grade. This result may also indicate cancer.

On the other hand, HPV tests can be positive, meaning high-risk HPV is present, or negative, meaning high-risk HPV is not present.

If a person receives a positive result, the doctor may recommend:

  • waiting for 6–12 months before getting a repeat test
  • getting a colposcopy, a test that aims to find abnormal cells in the cervix, usually after an abnormal Pap result
  • getting a biopsy, where a doctor removes a small tissue sample to send to the lab for analysis
  • receiving treatment for high-grade cervical changes

Around 5–10% of all cancers have links to inherited gene mutations, according to the ACS. This puts certain people at a higher risk of developing certain types of cancer.

Examples of cancers that can be hereditary include:

The ACS notes that cervical cancer may run in some families, but no specific genetic mutation has been identified for cervical cancer. This means doctors cannot determine whether a person is likely to develop cervical cancer based on genetic information such as DNA tests.

A 2020 study found that universal gene testing could detect more heritable genetic mutations than targeted testing. Similarly, a 2019 study also mentioned that multi-gene panel testing for hereditary cancer risk is more efficient and sensitive than traditional testing.

The following are common questions asked about HPV blood tests and Pap smears.

Can a blood test replace a Pap smear?

No. HPV stays on the skin and mucosal surfaces and changes cervical cells. Only the collection of cell samples done for Pap smears can detect these cell changes.

How much does a Pap smear cost?

The cost varies. For people without insurance, the test ranges from $25–60. This fee does not include the visit and pelvic exam cost.

How much does an HPV test cost?

HPV tests can cost between $30–100, depending on where the person gets them. This excludes the clinic or visit fee.

How often does a person need testing?

Following the 2020 American Cancer Society Cervical Screening Guidelines, people ages 25–65 years should have an HPV test every 5 years. If this is not possible, they should get a Pap test every 3 years or an HPV/Pap co-test every 5 years.

Cervical cancer is one of the most common cancers in women and is usually curable with early detection. Every woman ages 25 years and above should routinely undergo screening to help prevent cervical cancer.

While people may prefer less invasive screening tests for cervical cancer, Pap smears and HPV DNA tests are still the gold standard for cervical cancer screening.