Stool occult blood test

Overview

A stool occult blood test looks for tiny amounts of blood in your poo that you cannot see with your eyes. It is often used to check for problems in the digestive system, such as polyps or early signs of bowel cancer. The test is simple and painless – you collect a small sample of your stool at home and send it to a lab.

Yes, it is a common screening test, especially for adults aged 50 and older. Many countries use it as a first step to detect bowel cancer early.

It is used in adults, mainly those at average risk of bowel cancer. It can also be recommended for people with symptoms like stomach pain or changes in bowel habits, or those with a family history of bowel problems.

Symptoms

Causes

Main causes

• The test detects hidden blood, which can come from many places in the digestive tract.
• Common causes include haemorrhoids (piles), anal fissures, stomach ulcers, or inflammation in the gut.
• It can also be caused by polyps (small growths) or bowel cancer, which is why the test is used for early detection.

Risk factors

• Being over 50 years old increases the chance of bowel problems.

When to see a doctor

See a doctor urgently if:

• If you see blood in your poo – bright red or dark/black – especially if you also have stomach pain or weight loss.
• If you have a positive result from a stool occult blood test – your doctor will want to discuss next steps.

Book a routine appointment if:

• If you are aged 50 or over and have not had the test, ask your GP about screening.
• If you have a family history of bowel cancer, you might be offered the test earlier.

Diagnosis

The stool occult blood test is a screening tool, not a diagnosis. If the test is positive, your doctor will arrange further tests, usually a colonoscopy (a camera examination of your bowel).

Tests that may be done

• Stool occult blood test (Faecal Immunochemical Test – FIT – is the most common type in the UK)
• Colonoscopy – a thin, flexible tube with a camera is used to look inside your large bowel
• Sometimes a CT scan of your abdomen is done if a colonoscopy is not possible

What to expect at your appointment

For the stool test, you will receive a kit with instructions to collect a small sample of your poo at home. You usually need to avoid vitamin C, red meat, and certain medicines (like ibuprofen or aspirin) for a few days before collecting the sample. The kit is then posted to a lab. Results come back in a few days to a week.

Treatment

Treatment depends on what the test reveals. If no problem is found, no treatment is needed. If a condition is discovered, your doctor will discuss the best options for you.

Self-care at home

• If the cause is haemorrhoids or an anal fissure, eating more fibre, drinking plenty of water, and using gentle wipes can help.
• Avoid straining on the toilet.
• If you have a stomach ulcer, avoid alcohol, smoking, and NSAID painkillers like ibuprofen.

Medical treatments

Your doctor may prescribe medications to reduce stomach acid if ulcers are found, or antibiotics for certain infections. If polyps are seen during a colonoscopy, they can be removed during the same procedure. If bowel cancer is discovered, treatment may involve surgery, chemotherapy, or radiotherapy – your specialist will explain the options based on the stage and your overall health.

When is surgery considered?

Surgery may be needed to remove bowel cancer, large polyps that cannot be removed during colonoscopy, or to treat severe complications from conditions like diverticulitis. Your surgeon will explain the risks and benefits.

Living with this condition

If the test result is normal, you can live as usual. If a condition is found, follow your doctor's advice and attend any follow-up appointments.

Lifestyle tips

• Eat a balanced diet – plenty of fruits, vegetables, and whole grains.
• Limit red and processed meat.
• Stay active – aim for at least 30 minutes of moderate exercise most days.
• Avoid smoking and limit alcohol.
• Maintain a healthy weight.

Diet and exercise

Prevention

Not all causes of hidden blood can be prevented, but a healthy lifestyle can lower your risk of bowel cancer and other digestive problems.

Screening programmes

Screening with a stool occult blood test is the main way to catch bowel problems early, often before symptoms appear. In the UK, the NHS offers this test to everyone aged 50 to 74 every two years.

Complications

If left untreated

• If hidden blood is caused by a serious condition like bowel cancer, not following up can allow the disease to progress.
• Chronic bleeding can lead to anaemia (low red blood cells), causing tiredness and weakness.
• Bleeding from ulcers may continue and cause more pain or complications.

Long-term outlook

With regular screening and follow-up, most bowel problems can be caught early and treated successfully. Even bowel cancer has a very good outlook when found at an early stage. Your doctor will guide you through the next steps.

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