High negative predictive value of a normal faecal calprotectin in patients with symptomatic intestinal disease

Abstract

Background Calprotectin is a heat stable intracellular protein shed by neutrophils into the intestinal lumen in response to infl ammation. Lack of specifi city makes its role in the assessment of infl ammatory bowel disease uncertain. However, the strength of faecal calprotectin testing may lie in its negative predictive value (NPV) rather than positive predictive value (PPV) of organic intestinal disease. Objectives To determine whether a normal faecal calprotectin in new patients with symptoms safely predicts for functional intestinal disease. Methods To determine the predictive values of normal and raised faecal calprotectin by retrospective review of outcomes in consecutive primary care referrals into secondary care. Patients aged 16-60 years (mean age 41 years; 70% female patients) with intestinal symptoms were identifi ed. 500 referrals had a normal faecal calprotectin and 130 had a raised result. 'Fast track' referrals were excluded. Outcome measures were the NPV of a normal faecal calprotectin and PPV of a raised faecal calprotectin. Results Normal faecal calprotectin had an NPV of 0.964 for excluding symptomatic organic intestinal disease. Signifi cant incidental non-intestinal (3.6%) and intestinal (6.4%) diseases were also identifi ed. Mean follow-up was 4.8 years with no diagnostic revisions. In the raised faecal calprotectin cohort, the PPV for organic intestinal disease was 0.7. Conclusions A normal faecal calprotectin safely predicts for functional intestinal disease. It may represent a powerful screening tool for excluding organic intestinal disease in primary care. A prospective primary care based study is needed.

Evaluation of a faecal calprotectin care pathway for use in primary care

“…It has now developed an evidence-based care pathway for FC as a triage tool to facilitate the initial clinical assessment of patients presenting with lower gastrointestinal symptoms (Turvill, 2012;2014). The care pathway is designed to optimize the negative and positive predictive values (NPV and PPV) of FC.…”

Faecal calprotectin testing for differentiating amongst inflammatory and non-inflammatory bowel diseases: systematic review and economic evaluation

“…In a study amongst those with borderline calprotectin levels (> 50 but < 150 g/g), Demir et al (2012) 45 found no significant difference with NSAID use. Conversely, Turvill (2012) 46 reported that 14% of people referred from primary care with intestinal symptoms, and who had raised calprotectin, had a final diagnosis of NSAID enteropathy.…”

Faecal calprotectin in patients with suspected colorectal cancer: a diagnostic accuracy study

“…14 The NPV of FC for all organic enteric disease was lower than is seen in a younger cohort, because of the increased incidence of noninflammatory enteric disease in the elderly (such as microscopic colitis and pancreatic insufficiency). 4 Diverticulosis in the absence of inflammation was a diagnosis made on occasion by the responsible clinician. Having established its safety, the utility of FC next depends on its PPV.…”

“…However, should it be sufficiently sensitive, FC might differentiate much organic enteric disease from functional disorders, such as irritable bowel syndrome (IBS). [1][2][3][4] This would empower the expectant treatment of low-risk patients and the cost-effective identification of those requiring urgent investigation.…”