Diagnostic accuracy of faecal calprotectin in a symptom-based algorithm for early diagnosis of inflammatory bowel disease adjusting for differential verification bias using a Bayesian approach

Anna Viola, Andrea Fontana, Alessandra Belvedere, Riccardo Scoglio, Giuseppe Costantino, Aldo Sitibondo, Marco Muscianisi, Santi Inferrera, Lucia Maria Bruno, Angela Alibrandi, Gianluca Trifirò, Walter Fries

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Diagnostic delay in IBD is a major problem and diagnosis is frequently arrived when irreversible damage has already occurred. This study evaluated accuracy of faecal calprotectin (fCAL) integrated with diagnostic criteria for early diagnosis of IBD in a primary care setting. Methods: General practitioners (GPs) were trained to recognize alarm symptoms for IBD classified as major and minor criteria. Fulfilment of one major or at least two minor criteria was followed by free fCAL testing and a visit by an IBD specialist and follow-up over 12 months. All patients with positive fCAL testing, i.e., ≥70 μg/g underwent colonoscopy. The diagnostic accuracy of fCAL was estimated after adjusting for differential-verification bias following a Bayesian approach. Results: Thirty-four GPs participated in the study and 133 patients were tested for fCAL between July 2016 and August 2017. Positivity of fCAL was seen in 45/133 patients (34%) and a final IBD diagnosis was made in 10/45 (22%). According to the threshold of 70 μg/g, fCAL achieved a sensitivity of 74.8% (95%CI: 39.10–96.01%), a specificity of 70.4% (95%CI: 61.76–78.16%) and an overall diagnostic accuracy of 70.6% (95%CI: 61.04–78.37%). As for prognostic accuracy, despite positive predictive value being low, 21.9% (95%CI: 11.74–35.18%), the negative predictive value was definitely higher: 96.2% (95%CI: 84.96–99.51%). Conclusions: fCAL with a threshold set at 70 μg/g seems to represent a potentially reliable negative test to be used in primary care settings for patients with symptoms suggestive of IBD.

Original languageEnglish
Pages (from-to)1176-1184
Number of pages9
JournalScandinavian Journal of Gastroenterology
Volume55
Issue number10
DOIs
Publication statusPublished - Oct 2 2020

Keywords

  • diagnostic accuracy
  • Diagnostic delay
  • early diagnosis

ASJC Scopus subject areas

  • Gastroenterology

Fingerprint Dive into the research topics of 'Diagnostic accuracy of faecal calprotectin in a symptom-based algorithm for early diagnosis of inflammatory bowel disease adjusting for differential verification bias using a Bayesian approach'. Together they form a unique fingerprint.

Cite this