Home stool tests have made it far easier to check on your gut health without a clinic visit, but they are not all the same. Three of the most useful tests each answer a completely different question. Understanding what each one measures helps you choose the right test for your situation rather than guessing.
FIT: looking for hidden blood
The Faecal Immunochemical Test (FIT) detects tiny, non-visible traces of blood in the stool. It is the key test used in bowel cancer screening, because early bowel cancers and pre-cancerous polyps can bleed in amounts far too small to see. A positive FIT is not a diagnosis; it is a signal that further investigation, usually a colonoscopy, is worthwhile.
FIT answers the question: is there hidden bleeding that needs explaining?
Calprotectin: measuring gut inflammation
Faecal calprotectin is a marker released into the stool when the lining of the bowel is inflamed. Its main value is helping to distinguish inflammatory bowel disease (such as Crohn's or ulcerative colitis), where the level tends to be raised, from irritable bowel syndrome (IBS), where it is usually within the normal range despite troublesome symptoms.
Calprotectin answers the question: is my gut inflamed, or is this more likely a functional problem like IBS?
Microbiome: mapping gut balance
A gut microbiome test maps the balance of bacteria living in your gut, along with broader markers of gut health and wellness. Rather than screening for a specific disease, it gives a wellness-oriented picture of diversity and balance, which can inform diet and lifestyle choices.
Choose the right stool test
FIT and calprotectin home tests answer different questions — blood versus inflammation. Kits posted to you.
Choose the right stool testChoosing the right test
Because each test answers a different question, they are not interchangeable. As a rough guide:
- Worried about bleeding or bowel cancer risk — a FIT test
- Persistent symptoms and want to know if there is inflammation — calprotectin
- Interested in general gut wellness and bacterial balance — a microbiome test
Some people benefit from more than one, and the right combination depends on your symptoms and history.
When to see a doctor
Stool tests are a helpful starting point, but results should be interpreted alongside your symptoms and, especially for FIT and calprotectin, with a clinician. A raised result points towards further assessment, not a self-managed conclusion. If you have red-flag symptoms such as ongoing bleeding, unexplained weight loss, or a persistent change in your bowel habit, see your GP promptly, whatever a home test shows. Testing supports medical assessment; it does not replace it.
Choose the right stool test
Book online with OneMedicine — CQC-registered clinic in Birmingham, or a home visit / local clinic nationwide. Doctor-reviewed results, most within 24 hours.
Book now
Specialist interest: Cardiovascular Medicine · OneMedicine, CQC-registered clinic