Cervical screening

Cervical screening


A cervical screening test (previously known as a smear test) is a method of detecting abnormal cells on the cervix. The cervix is the entrance to the womb from the vagina.

Detecting and removing abnormal cervical cells can prevent cervical cancer.

Cervical screening isn’t a test for cancer; it’s a test to check the health of the cells of the cervix. Most women’s test results show that everything is normal, but for around 1 in 20 women the test shows some abnormal changes in the cells of the cervix.

Most of these changes won’t lead to cervical cancer and the cells may go back to normal on their own. However, in some cases, the abnormal cells need to be removed so they can’t become cancerous.

About 3,000 cases of cervical cancer are diagnosed each year in the UK.

It’s possible for women of all ages to develop cervical cancer, although the condition mainly affects sexually active women aged 30 to 45. The condition is very rare in women under 25.

The cervical screening programme

The aim of the NHS Cervical Screening Programme is to reduce the number of women who develop cervical cancer and the number of women who die from the condition. Since the screening programme was introduced in the 1980s, the number of cervical cancer cases has decreased by about 7% each year.

All women who are registered with a GP are invited for cervical screening:

  • aged 25 to 49  every three years
  • aged 50 to 64  every five years
  • over 65  only women who haven’t been screened since age 50 or those who have recently had abnormal tests

Being screened regularly means any abnormal changes in the cells of the cervix can be identified at an early stage and, if necessary, treated to stop cancer developing.

However, cervical screening isn’t 100% accurate and doesn’t prevent all cases of cervical cancer.

Screening is a personal choice and you have the right to choose not to attend.

Read about:

What happens when you go for cervical screening?

Booking your test

You’ll receive a letter through the post asking you to make an appointment for a cervical screening test. The letter should contain the details of the place you need to contact for the appointment.

Most women choose to go to their GP practice, although it may also be available at a well woman clinic or sexual health clinic. Screening is usually carried out by the practice nurse. You can ask to have a female doctor or nurse.

If possible, try to book an appointment during the middle of your menstrual cycle (usually 14 days from the start of your last period), as this can ensure a better sample of cells is taken.

If you use a spermicide, a barrier method of contraception or a lubricant jelly, you shouldn’t use these for 24 hours before the test, as the chemicals they contain may affect the test.

Your screening appointment

The cervical screening test usually takes around five minutes to carry out. You’ll be asked to undress from the waist down and lie on a couch, although you can usually remain fully dressed if you’re wearing a loose skirt.

The doctor or nurse will gently put an instrument, called a speculum, into your vagina. This holds the walls of the vagina open so the cervix can be seen. A small soft brush will be used to gently collect some cells from the surface of your cervix.

Some women find the procedure a bit uncomfortable or embarrassing, but for most women it’s not painful. If you find the test painful, tell the doctor or nurse, because they may be able to reduce your discomfort. Try to relax as much as possible, because being tense makes the test more difficult to carry out. Taking slow, deep breaths will help.

The cell sample is then sent off to a laboratory for analysis and you should receive the result within two weeks.

HPV testing

Changes in the cells of the cervix are often caused by the human papilloma virus (HPV). There are more than 100 different types of HPV. Some types are high risk and some types are low risk. HPV-16 and HPV-18 are considered to be highest risk for cervical cancer.

After successful trials, HPV testing has been incorporated into the NHS Cervical Screening Programme.

If a sample taken during the cervical screening test shows low-grade or borderline cell abnormalities, the sample should automatically be tested for HPV. If HPV is found in your sample, you should be referred for a colposcopy for further investigation and, if necessary, treatment. If no HPV is found, you’ll carry on being routinely screened as normal.

If your sample shows more significant cell changes, you’ll be referred for colposcopy without HPV testing.

In some areas, a test for HPV is the first test on the screening sample. In these cases, the sample is only checked for abnormal cells if HPV is found. If HPV isn’t found, you’ll be offered a screening test again in three to five years (depending on your age).

Read about the results of cervical screening tests.

Why cervical screening is offered

Cervical screening is offered because it can detect abnormal cell changes in the cervix (the lower part of the womb) that could potentially develop into cervical cancer.

Abnormal cells that are picked up during cervical screening often return to normal on their own, so waiting may be recommended.

However, if more significant abnormalities are detected at an early stage, there is the option of having treatment to remove them before they have a chance to become cancerous.

Since the screening programme was introduced in the 1980s, the number of cervical cancer cases has decreased by about 7% each year and it’s estimated that up to 5,000 cases of cervical cancer are prevented each year in the UK because of cervical screening.

What causes abnormal cell changes in the cervix?

Abnormal changes in the cells of the cervix can be caused by certain high-risk types of human papilloma virus (HPV).

HPV is the name of a family of common viruses that affect the skin and the mucus membranes (moist tissue that lines parts of the body), such as those in your cervix, anus, mouth and throat.

HPV is very common and is passed on through skin-to-skin contact. It’s estimated that 8 out of 10 people in the UK are infected with HPV at some point during their lifetime. For most people, the virus goes away without treatment and doesn’t cause any harm.

However, infection with some types of HPV can cause abnormal cell growth, which can lead to cervical cancer. Other forms of HPV cause genital warts.

The high-risk types of HPV that can cause abnormalities in the cells of your cervix are transmitted through sexual contact. This includes penetrative sex as well as other types of sexual contact, such as skin-to-skin contact of the genital area, or using sex toys. Because most types of HPV, including high-risk types, don’t cause any symptoms, you or your partner could have the virus for months or years without knowing it.

Can HPV be prevented?

It can be very difficult to prevent HPV, which is one of the reasons cervical screening is so important.

Using a condom during sex can reduce your risk of developing an HPV infection, but as condoms don’t cover the entire genital area and are often put on after sexual contact has begun, they’re not guaranteed to prevent the spread of HPV.

A vaccination offering some protection against HPV is now offered to all girls aged 12-13 as part of the NHS Childhood Vaccination Programme. This has been shown to provide effective protection against HPV for at least eight years, but it’s not yet known how long protection lasts beyond this.

Read more about the HPV vaccination.

How common are abnormal results?

For every 100 women who have cervical screening, about 6 will have an abnormal result.

It’s very rare for cancer to be diagnosed from the results of a cervical screening test. Less than 1 in 1,000 test results show invasive cancer.

Are there any disadvantages of screening?

Although cervical screening can help to prevent cervical cancer, there are some potential disadvantages associated with it. These include:

  • potential discomfort, embarrassment or (less commonly) pain during the screening test
  • a very small chance of getting incorrect results, which could lead to abnormalities being missed or unnecessary distress and treatment
  • a chance of having unnecessary treatment if the abnormalities would have corrected themselves naturally
  • some treatments used to remove abnormal cells may increase your risk of giving birth prematurely (before the 37th week of pregnancy) if you get pregnant in the future

However, cervical screening is offered to women aged 25-64 in England because the potential benefits of screening are believed to outweigh these risks.

Deciding whether or not to have a screening test is your choice. To help you decide, you can also read the NHS Cervical Screening leaflet (PDF, 453kb).

If you don’t want to be invited for screening in the future, contact your GP and ask to be removed from their list of women eligible for cervical screening. If you change your mind at a later date, you can simply ask your GP to put you back on the list.

When cervical screening is offered

Women aged 25-64 who are registered with a GP are automatically invited for cervical screening.

This includes women who have had the HPV vaccination, as the vaccine doesn’t guarantee complete protection against cervical cancer.

Invitation letters

Women registered with a GP will receive a letter inviting them to make an appointment, along with further information about cervical screening.

The letters should be sent out to women:

  • aged 25 to 49  every three years
  • aged 50 to 64  every five years
  • over 65  only women who haven’t been screened since age 50 or those who have recently had abnormal tests 

Women under 25 could be invited up to six months before their 25th birthday and you can book your screening appointment as soon as you get the invitation.

If you haven’t had a cervical screening test within the appropriate time, you may be offered one when you next visit your GP or family planning clinic. You can also contact your GP practice to book a screening appointment if you’re overdue one.

Make sure your GP has your correct name and address, and let them know of any changes so you can be contacted when you’re due to have a screening test.

If you’re not sure when your next screening test should be, or if you have any questions about the NHS Cervical Screening Programme, ask your GP or practice nurse.

Alternative screening locations

If you’re not registered with a GP practice, or if you don’t wish to be screened at your GP practice, screening may also be available at a well woman clinic or sexual health clinic.

Find your nearest sexual health services.

When a screening test may not be recommended

In some cases, you may not need cervical screening or it may be recommended that you delay having a screening test. These situations are described below.

Women with symptoms of cervical cancer

Cervical cancer screening is not a test for symptoms of cervical cancer. You should see your GP if you have symptoms such as:

  • unusual bleeding
  • pain and discomfort during sex
  • unusual vaginal discharge

If necessary, your GP can refer you to a gynaecologist.

Women who haven’t had sex

The risk of cervical cancer is very low in women who have never had sex. As the risk is so low, women in this group may choose not to have cervical screening when invited.

However, if you’re not currently in a sexual relationship but have been in the past, it’s recommended that you have regular cervical screening.

Pregnant women

Cervical screening tests aren’t usually recommended while you’re pregnant, unless you’ve missed previous screening appointments or you’ve had abnormal results in the past.

If you’re pregnant and have always attended your screening appointments without having abnormal results, it’s usually recommended that you wait until three months after giving birth before having a screening test.

If you’re invited to cervical screening while pregnant and you’re unsure whether you need to be tested, contact your GP or practice nurse for advice.

Women aged 65 and over

Women aged 65 and over whose last three test results were normal aren’t invited for further cervical screening tests. This is because it’s very unlikely that women in this group will go on to develop cervical cancer.

If you’re over 64 and have had abnormal test results, you’ll continue to be invited for screening until the cells return to normal. Women aged 65 and over who have never had screening are entitled to a test.

Women who have had a total hysterectomy

Women who have had a total hysterectomy (an operation to remove the womb and cervix) will no longer be invited to attend cervical screening, as it’s not necessary.

Women who have had a hysterectomy that has left all or part of the cervix in place will be invited for screening once their post-operative care has finished.

Women who have had a total hysterectomy to treat cancer, or who had cervical intra-epithelial neoplasia (CIN, a type of cervical cell change that can lead to cancer) at the time of having a total hysterectomy, may need another type of test called a vault smear.

This is where a sample of cells is taken from the vagina, close to where the cervix used to be. Vault smears are part of the follow-up treatment for hysterectomy and aren’t part of the cervical screening programme.

Results of cervical screening

The results of your screening test will be sent to you in the post, with a copy sent to your GP.

Before you leave your screening, ask when your results are expected and how you’ll receive them. In some cases, you may need to contact your GP or clinic to get your results.

The Cervical Screening Programme aims to notify people of their results within 14 days.

The types of screening result you may get depends on how your screening sample was tested. The first test carried out on the cell sample is either:

If HPV primary screening is carried out first in your area, you’ll receive a leaflet with your screening invitation containing more information.

Test results for abnormal cells

If the first test carried out on your sample is to look for abnormal cells (cytology), then you should receive one of the following results.


A normal test result means no abnormal cell changes have been found. No action is needed and you don’t need another cervical screening test until it’s routinely due.


You may be told you need to have a repeat test because the first one couldn’t be read properly. This may be because:

  • not enough cells were collected
  • the cells couldn’t be seen clearly enough
  • an infection was present

You’ll be asked to go back so another sample of cells can be taken, usually after about three months.


If you have abnormal results, you may be told you have:

  • borderline or low-grade changes (called dyskaryosis)
  • moderate or severe (high-grade) dyskaryosis

If your result is low-grade, it means that although there are some abnormal cell changes, they’re very close to being normal and may disappear without treatment.

In this case, your sample will be tested for HPV. If HPV isn’t found, you’re at very low risk of developing cervical cancer before your next screening test. You’ll be invited back for routine screening in three to five years (depending on your age). If HPV is found, you’ll be offered an examination called colposcopy, which looks at the cervix more closely.

If your result is high-grade dyskaryosis, your sample won’t be tested for HPV, but you’ll be offered colposcopy (an examination of the cervix) to check the changes in your cervical cells.

All these results show you have abnormal cell changes. This doesn’t mean you have cancer or will get cancer. It just means that some of your cells are abnormal, and if they’re not treated they may develop into cervical cancer.

HPV primary screening test results

If your sample is first tested for HPV (known as HPV primary screening), then what happens next depends on whether HPV is found.

HPV negative means no HPV was found. In this case, no further tests need to be carried out on the sample, and you’ll simply be called back for screening again in three to five years (depending on your age).

HPV positive means HPV has been found in your sample. In this case, the sample will also be tested for abnormal cells. If no abnormal cells are found, you’ll be asked to come back for screening again in 12 months to see if the HPV has gone.

If abnormal cells are found along with an HPV positive result, you’ll be referred for colposcopy.


A colposcopy is a simple examination that uses a special microscope called a colposcope to examine your cervix. Having colposcopy is very much like having cervical screening. The colposcope doesn’t go inside you. It can identify the extent of abnormal cells and helps to determine whether you need treatment.

A small sample of tissue (biopsy) may also be taken from your cervix during colposcopy.

Sometimes you’ll be offered treatment to remove abnormal cells at the same time as your colposcopy examination. More extensive types of treatment may require a separate appointment.

Read more about colposcopy and the different types of treatment to remove abnormal cells in the cervix.