Summary

• Almost all cervical cancer is caused by long-term infection from certain types of the human papillomavirus (HPV).
• Cervical screening testing helps prevent cervical cancer from developing by looking for signs of HPV.
• Sometimes a second test is needed to look for possible cell changes in the cervix (the lower part of the uterus or womb). This is the cervical co-test.
• Both these tests are done by the same laboratory using the same sample.

What is the cervical co-test and what is its role in screening for cervical cancer?

Screening and monitoring of cervical cancer can sometimes need two tests. The cervical screening test is used as the initial screening test. This test checks for Human Papilloma Virus (HPV) infection which causes almost all cervical cancers. 

Depending on your clinical history and the result of your HPV test, it may be necessary to perform a second test.  This test is called the cervical co-test or Liquid Based Cytology (LBC) test. It examines cervical cells taken from the same sample as the HPV test for signs that cervical cancer is present or developing. 

These two tests have replaced the Pap smear which was used until 2017 to screen for cervical cancer. 

Using both these tests can identify more women or people with a cervix who may be at risk of developing cervical cancer than either test alone. If the results of either test are abnormal, further follow-up or testing might be recommended. 

Use of the cervical screening test and the cervical co-test in combination mean that it is only necessary to repeat the cervical screening test every five years if you receive a ‘not detected’ or low risk result from your screening test. 

Initial cervical screening or HPV testing alone 

The cervical screening or HPV test is used to detect high risk strains of HPV that can cause cancer of the cervix, the lower part of the uterus or womb. 

HPV is very common even in people who have only one partner.  In most cases, it will cause few symptoms, and the infection will clear up naturally — just as the body gets rid of cold and flu viruses.

For some people, the virus can cause skin warts, genital warts and laryngeal (throat) polyps. It can also cause oral, anal, cervical, penile, and other forms of genital cancer. In some cases, it may develop into cervical cancer. 

For many people it will only be necessary to test for HPV. If you do not have symptoms of cervical cancer, and your sample does not show any of the high-risk strains of HPV which are known to cause cervical cancer, you will be asked to return for a repeat test in five years.

If the HPV test identifies a high-risk strain, the laboratory will then organise for the cervical co-test or LBC to be done.

HPV and LBC testing requested and performed together

Under certain circumstances the HPV and LBC tests will be done at the same time without first waiting for the results of the HPV test. This may be requested if:

1. You already have signs or symptoms that suggest cervical cancer such as:

• Unusual or abnormal vaginal bleeding (after sex, between periods or post-menopause)
• Pain during sex, or
• Unusual vaginal discharge.

2. You do not have symptoms but are being followed up after diagnosis and treatment, for example, if:

• You have received treatment for a possible high-grade squamous intraepithelial lesion (pHSIL) or a high-grade squamous intraepithelial lesion (HSIL), and you are being checked to see if the treatment has been effective.
• You have had an adenocarcinoma in situ (AIS) diagnosed and are being monitored to see if it has developed into cervical cancer.
• You are the daughter of a mother who was treated with the drug Diethyl-stilboestrol. This is because you are at greater risk of developing cervical cancer if you were exposed to this drug when your mother was pregnant with you.

In a cervical co-test the sample from your cervix is put into a tube containing liquid. After processing to remove mucus, blood, and debris, the sample is examined under a microscope by a cytologist (a specialist scientist) and/or a cytopathologist (specialist pathologist). Both will look for precancerous cell changes or cervical cancer. This is called liquid-based cytology (LBC).

Having the test

Sample

A sample of cells is taken from the cervical area, using a type of spatula, swab, or brush. The cells are transferred to a special preservative liquid and are transported to the laboratory.

Self-collection is available (see cervical screening test) to test for signs of the virus but if you need a cervical co-test to check for cell changes you will need to have a another test sample collected by your doctor.

Any preparation

None.

Your results

For more on results see cervical screening test.

If your repeat HPV test is ‘not detected’ again in 12 months you can return to routine 5 yearly screening.

If any type of HPV is detected at your 12 month repeat test will need to have a colposcopy. This is an examination of your cervix which is usually performed by a gynaecologist. The specialist will insert a speculum into your vagina and put a small amount of liquid on to your cervix to highlight any abnormal areas. They will use a colposcope (like a pair of binoculars on a stand) to carefully examine the cervix and vagina. This examination takes 10-15 minutes.

Treatment
The treatment options following colposcopy may include:

• monitoring over a period of months to see if previously observed changes return to normal,
• cryosurgery that freezes and destroys infected cells, or
• procedures that remove the cancerous tissue. 

The cervical co-test will be used to monitor your progress.

Any more to know?

The risk of developing cervical cancer has been greatly reduced through the introduction of a HPV vaccine, Gardasil®. This vaccine is available for all females and males aged 12-25 through the government funded National Immunisation Program. 

However, the vaccine does not protect against all forms of HPV that can cause cancer. If you have ever been sexually active you should have screening every five years or until your doctor confirms it is safe for you to exit screening. 

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and if you have any symptoms that could suggest cervical cancer. These symptoms include abnormal bleeding, pain during sex or abnormal discharge. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods, medications or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record.

You and your healthcare provider can now access your results whenever and wherever needed. Get further trustworthy health information and advice from healthdirect.