Stool Test: Purpose, Preparation, and What Your Results Mean

What is a stool test?

A stool test (also called a faecal test) is a test that your doctor uses to analyse a sample of your stool (faeces) to diagnose a range of health conditions related to the digestive system.

The stool sample may be used to check for certain disease-causing micro-organisms, bacteria, viruses, and parasites or to look for signs of inflammation, digestive system disorders, infection, and some types of cancer.

Stool tests are a non-invasive and effective way for doctors to get a snapshot of what’s happening in your digestive tract and help diagnose a range of conditions.

Why do you need it?

You may require a stool test if you have symptoms that suggest an infection or other gastrointestinal conditions. These symptoms may include:

• Chronic diarrhoea:

  • More than a few days of diarrhoea, particularly if it is watery, might indicate infection or some other condition.

• Blood in stool:

  • This is one of the possible indications of bleeding within the digestive tract due to conditions such as haemorrhoids, ulcers, or even more serious conditions like colorectal cancer.

• Unintentional weight loss:

  • If you've been losing weight, it might be due to a digestive issue that requires examination.

• Abdominal pain or bloating:

  • Digestive disorders, infections, or food intolerances often manifest as pain or bloating, which may require testing for accurate diagnosis.

• Bowel habit changes:

  • Changes in bowel habits, constipation, diarrhoea, and changes in stool consistency may reflect gastrointestinal infections, disorders, and even precancerous changes in the gut.

It is also used for routine health screening, in particular for detecting conditions such as colorectal cancer, parasitic infections, or bacterial infections.

If you are experiencing ongoing digestive issues, unexplained changes in your bowel habits, or symptoms like abdominal pain or blood in your stool, please consult a specialist. Request an appointment with Thomson Medical today for a stool test and receive the care you need.

How do I prepare for a stool test?

You might not need to do anything special before your stool test, but in some cases, your healthcare provider may give you specific instructions to follow.

For instance, your doctor might advise you to stop taking certain medications, such as antibiotics or laxatives, or to avoid foods that could affect your results. These instructions can vary depending on the type of test you’re having.

You may also need to collect more than one sample over a few days. It’s important to use a clean, dry container when collecting your sample—make sure it doesn’t come into contact with urine or toilet paper.

To be sure you're doing everything correctly, always check with your provider ahead of time to find out if there’s anything you need to avoid or do differently. This procedure helps ensure your test results are as accurate as possible.

How stool tests work: types and methods?

When you provide a stool sample, laboratory professionals use different testing methods depending on what your doctor needs to know about your digestive health. Here are the main types of stool tests and how they work:

Each test provides your healthcare provider with different information about your digestive health, helping them make accurate diagnoses and recommend appropriate treatments for your specific situation.

What do the results mean?

After your stools are analysed, your doctor will interpret what the results mean for your health. Understanding your results can help you and your healthcare provider determine next steps.

Normal results

If your test results are normal, it indicates that your sample did not contain any concerning issues. Your stool showed no signs of infection, hidden blood, parasites, or other digestive problems. The result  is good news, though your doctor might still recommend additional testing if your symptoms continue.

Abnormal results

If your test shows something unusual, what the result means depends on the specific finding:

• Blood in stool could point to several possibilities. It might be from something minor like haemorrhoids, or it could indicate polyps, ulcers, or, in some cases, colorectal cancer. The amount and pattern of bleeding help your doctor determine the likely cause.

• Parasites or harmful bacteria in your sample typically mean you have a gastrointestinal infection. These infections often cause symptoms like diarrhoea, stomach cramps, or nausea. The good news is that once identified, many of these infections can be effectively treated.

• High levels of calprotectin suggest inflammation in your intestines. Such inflammation is commonly seen in conditions like Crohn's disease or ulcerative colitis. If you're already diagnosed with these conditions, this test helps monitor how well your treatment is working.

• Excess fat in your stool might indicate your body isn't properly absorbing nutrients. This can happen with conditions like coeliac disease, pancreas problems, or other digestive disorders that affect how your body processes food.

Remember that abnormal results don't always mean something serious — they simply guide your doctor toward what might be causing your symptoms so they can recommend appropriate next steps.

FAQ

What does a stool test check for?

A stool test involves analysing a sample of faeces in a laboratory to look for signs of health issues affecting your digestive system. It can identify the presence of infections — such as harmful bacteria, viruses, or parasites — as well as hidden blood, undigested food, and markers of inflammation.

These laboratory tests support the diagnosis of gastrointestinal infections, inflammatory bowel conditions, and malabsorption disorders, and they can aid in the early detection of bowel cancer.

What if a stool test is positive?

A positive result means the test has picked up something abnormal in your stool, such as blood, signs of infection, or parasites. While the result does not always indicate a serious condition, it usually signals the need for further medical care or investigation to determine the cause and start effective treatment.

How long do stool test results take?

Most laboratory tests on stool samples take between 1 to 3 days, but this can vary depending on the specific test being performed and whether additional cultures or analyses are needed. Some infectious disease screenings may take longer if further evaluation is required.

What illnesses can be detected from a stool sample?

Stool tests can help identify various health conditions, including:

• Gastrointestinal infections:

  • Bacterial, viral, or parasitic infections

• Inflammatory bowel diseases:

  • Conditions like Crohn’s disease and ulcerative colitis

• Colorectal cancer:

  • Detection of hidden blood in the stool

• Malabsorption disorders:

  • Such as coeliac disease

• Digestive issues:

  • Conditions like pancreatic insufficiency

What should I avoid before a stool test?

To ensure accurate results, avoid the following before a stool test:

• Red meat:

  • For tests like the FOBT, red meat may cause false positives.

• Medications:

  • Avoid antibiotics, anti-diarrhoeal drugs, or laxatives unless your doctor advises otherwise.

• Enemas or laxatives:

  • Avoid using these unless directed by your healthcare provider.

Can stool tests detect colon problems?

Yes, stool tests can help detect signs of colon issues such as bleeding, inflammation, and infections. They can also be used for early screening of colon cancer by detecting hidden blood in the stool. However, for a definitive diagnosis, additional tests like a colonoscopy may be required.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations based on your medical conditions, request an appointment with Thomson Medical.