What is a stool test?

Samples of poo that you collect for a test are called 'stool samples'. Poo is sometimes called faeces or bowel motions. Sometimes your poo needs to be checked by a test in a laboratory. The stool test can show what is causing your health problem.

There are different laboratory tests that can be done. It depends on why you need the stool test. These tests are sometimes also called faecal tests.

Why might I need to have a stool test?

Stool tests investigate causes of diarrhoea or blood in the stool.

Diarrhoea and blood in the stool can be caused by many things, such as:

• an infection
• inflammatory bowel disease
• poor absorption of food
• bowel cancer

What type of stool test can look for bowel cancer?

An immunochemical faecal occult blood test (iFOBT) is used for bowel cancer screening. The iFOBT test is called a screening test because it checks a lot of healthy people in the community.

The test looks for blood in your faeces and can show up tiny amounts of blood that you can't see.

The aim is to find any cancer early when it can easily be treated. The test can show bowel cancer even if you feel well.

All Australians aged between 45 and 74 years can have a free iFOBT every 2 years. This is done through the National Bowel Cancer Screening Program.

What type of stool test can show an infection?

Stool microscopy and culture

A scientist can look at your stool sample using a microscope. They can also try and grow a germ from your stool sample. This is called doing a 'culture' of the stool sample.

Other tests can look for the DNA or RNA of germs that cause disease. These tests can tell the doctor if there are bacteria, viruses or parasites in your stool.

If the test shows bacteria or a parasite, you may need to take medicine for it. If nothing is found on the test you should see your doctor if you are not getting better.

Gastroenteritis

Your doctor may ask you to do a stool test if you have vomiting and diarrhoea that lasts more than a few days. This can tell them the germ causing your gastroenteritis. Most of the time gastroenteritis gets better by itself and doesn't need a stool test.

Testing can also be helpful if there is an outbreak of vomiting or diarrhoea in a school, or aged care setting. Sometimes tests are needed if you work in the food industry or in a healthcare setting.

Another reason to have a stool test is if you have gastroenteritis and have recently returned from overseas.

Clostridium difficile stool test

Clostridium difficile (also known as C. diff) is a type of bacteria that can cause diarrhoea. It often starts after you have taken antibiotics. It shows up on a stool test.

Helicobacter pylori stool test

Helicobacter pylori is a type of bacteria that can cause stomach ulcers and stomach cancer. It can be found using several different types of tests, including a stool test.

What types of stool test can check for other health conditions?

There are other stool tests which are sometimes done for certain health conditions.

• Faecal calprotectin — this looks for inflammation in your bowel. It may help your doctor work out if you have inflammatory bowel disease. It can also measure the amount of inflammation in your bowel. This is important if you have a flare-up.
• Faecal elastase and fat — these are tested to see if your pancreas is working properly. Your doctor might ask you to do this test if there are signs that you are not absorbing food well.

How do I collect a stool sample?

Faecal occult blood test

Stool samples for iFOBTs are easily collected in the privacy of your own home. You do not need to go to the doctor. You will get a free kit in the mail with instructions. This is part of the National Bowel Cancer Screening Program. Once you have done the test, you will need to send the samples to the laboratory. All the instructions are in the test kit.

Stool tests for infection

Your doctor or pathology collector will give you sterile jars to collect your sample in. Get a clean plastic container and line it with toilet paper. Put this in the toilet so it can catch your faeces. Take some of the faeces from the container and put it into the sterile jar. You can scoop the faeces into the jar.

Wear gloves and wash your hands carefully after doing the test. This will help prevent you passing on an infection to others. Throw the leftover faeces that is in the plastic container down the toilet.

Make sure you don't let any urine (wee) or water go into the jar. If you need to pass urine, do this before collecting your stool sample.

You will need to take the sample to the laboratory as soon as possible. You may need to store the sample in the fridge until you deliver it. Talk to your doctor or pathology collector about what you need to do.

How will I get results of my stool test?

The results from the IFOBT should be sent to you in about 4 weeks. Your doctor will also get your results, if you named them on the form you sent in with the sample.

If your test is positive, make an appointment with your doctor to talk about what to do next.

The results of all other stool test, will be sent to your doctor. It's very important to talk to your doctor about your test results.

Resources and support

The Australian Government offers guidelines on the National Bowel Cancer Screening Program.

You can request the iFOBT test kit if you are eligible. They are sent out to people aged between 50-74 years every 2 years. You can also ask for a test kit from the age of 45 years.

Queensland Health's patient collection sheet explains in simple steps how to collect a stool sample.

You can contact the National Cancer Screening Register on 1800 627 701.

Read the home test kit instructions in English and other languages.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.