The Role of FIT and Calprotectin in Early Detection and Accurate Diagnosis of Bowel Disease

Colorectal cancer remains one of the most significant global health challenges, ranking as the third most common cancer and the second leading cause of cancer-related death worldwide. An estimated 1.8 million new cases and approximately 880,800 deaths were reported globally in 2018 alone (Bray et al., 2018). These figures highlight the urgent need for improved screening, early detection, and diagnostic accuracy in both primary and specialist care settings.

Why Early Detection Matters

One of the key challenges in colorectal cancer is that symptoms often present late, when the disease may already be advanced. Common symptoms such as persistent changes in bowel habits, blood in the stool, abdominal pain, unexplained weight loss, and appetite changes are frequently associated with later stages of disease (NICE, 2015).

However, outcomes differ dramatically depending on when the disease is diagnosed. Evidence shows that early-stage colorectal cancer has a 5-year survival rate of over 90%, compared to less than 10% when diagnosed at an advanced stage (NCIN, 2009). This stark contrast reinforces the importance of proactive screening rather than symptom-driven investigation.

The Role of FIT in Colorectal Cancer Screening

The Faecal Immunochemical Test (FIT) has become a cornerstone of colorectal cancer screening globally. FIT detects hidden (occult) blood in stool, which may be an early indicator of colorectal cancer or advanced adenomas.

Its advantages include:

• Non-invasive and easy sample collection by patients

• Suitable for large-scale population screening

• Effective triage tool for identifying patients requiring colonoscopy

At Diagno, we support access to reliable FIT solutions, including those developed by leading global manufacturers such as Eiken Chemical, enabling clinicians to detect disease earlier and streamline referral pathways.

Beyond Cancer: The Importance of Calprotectin

While FIT plays a critical role in cancer detection, many patients present with non-specific gastrointestinal symptoms that may be caused by a range of conditions, including functional disorders such as IBS or inflammatory diseases such as IBD.

This is where faecal calprotectin becomes a valuable diagnostic tool.

Calprotectin is a protein released by neutrophils during inflammation in the intestinal mucosa. Elevated levels in stool are strongly associated with intestinal inflammation, making it a useful biomarker for:

• Differentiating Inflammatory Bowel Disease (IBD) from Irritable Bowel Syndrome (IBS)

• Monitoring disease activity and treatment response in IBD patients (Burri et al., 2011; Schoepfer et al., 2010)

Clinical guidelines strongly support its use:

• The National Institute for Health and Care Excellence (NICE) recommends faecal calprotectin to aid in differentiating IBD from IBS (NICE DG11, 2013)

• The American College of Gastroenterology (ACG) and European Crohn’s and Colitis Organisation (ECCO) also endorse its role in diagnosis and disease monitoring (Lichtenstein et al., 2018; Masser et al., 2019)

A commonly used threshold of 50 μg/g helps distinguish between functional and inflammatory conditions (NICE DG11, 2013).

A Combined Diagnostic Approach: FIT + Calprotectin

Emerging evidence supports the combined use of faecal haemoglobin (FIT) and faecal calprotectin in patients presenting with bowel symptoms.

A UK-based study demonstrated that this combination can effectively help rule out significant bowel disease, including colorectal cancer and IBD, with very high accuracy. Reported negative predictive values were:

• 100% for colorectal cancer

• 97.8% for high-risk adenomas

• 98.4% for IBD (Mowat et al., 2015)

This combined approach provides clinicians with a powerful, non-invasive triage tool in primary care, enabling:

• Improved diagnostic confidence

• More appropriate referral decisions

• Reduced burden on colonoscopy services

Diagno’s Role in Supporting Better Outcomes

At Diagno, we are committed to supporting clinicians with evidence-based, non-invasive diagnostic solutions that enhance patient care pathways.

By providing access to FIT (including Eiken solutions) and faecal calprotectin testing, we aim to:

• Promote earlier detection of colorectal cancer

• Improve differentiation between functional and inflammatory bowel disease

• Support more efficient and accurate clinical decision-making

In an environment where early intervention can significantly alter outcomes, integrating these diagnostic tools into routine clinical practice is no longer optional—it is essential.

References

Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A (2018). Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 68(6):394–424.

National Institute for Health and Care Excellence (NICE). Suspected cancer: recognition and referral (NG12). 2015.

National Cancer Intelligence Network (NCIN). Colorectal Cancer Survival by Stage - Data Briefing. June 2009.

Burri et al. Faecal Calprotectin in the Diagnosis of Inflammatory Bowel Disease. Biochemia Medica, 2011; 21(3): 245–253.

Tibble et al. A simple method for assessing intestinal inflammation in Crohn's disease. Gut, 2000; 47: 506–513.

Tibble et al. Use of surrogate markers of inflammation to distinguish organic from non-organic disease. Gastroenterology, 2002; 123: 450–460.

Montalto et al. Fecal calprotectin in relatives of ulcerative colitis patients. Am J Gastroenterol, 2007.

Schoepfer et al. Calprotectin correlates with endoscopic disease activity. Am J Gastroenterol, 2010.

NICE. Faecal calprotectin diagnostic tests for inflammatory diseases of the bowel (DG11). 2013.

Lichtenstein et al. ACG clinical guideline: management of Crohn’s disease in adults. Am J Gastroenterol, 2018.

Masser et al. ECCO-ESGAR Guideline for Diagnostic Assessment in IBD. Journal of Crohn’s and Colitis, 2019.

Mowat et al. Faecal haemoglobin and calprotectin as indicators of bowel disease in primary care. Gut, 2015.