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.
Testing for abnormal cells
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. But 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.
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.
But cervical screening isn’t 100% accurate and doesn’t prevent all cases of cervical cancer.
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.
The cervical screening test usually takes around 5 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 consultant 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 little uncomfortable or embarrassing, but for most women it’s not painful. If you find the test painful, tell the consultant as they may be able to reduce your discomfort. Try to relax as much as possible as 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 2 weeks.
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.
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.
The results of your screening test will be explained to you by your consultant. If the first test carried out on your sample is to look for abnormal cells (cytology), you should receive 1 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 back so another sample of cells can be taken.
If you have abnormal results, you may be told you have:
- borderline or low-grade changes (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.
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 cancer.