Diagnosing Inflammatory bowel disease using noninvasive applications of volatile organic compounds: a systematic review

ABSTRACT

Introduction: Inflammatory bowel disease (IBD) is a common disease with significant morbidity. Noninvasive diagnostic techniques are lacking in IBD. Currently, fecal calprotectin is a sensitive marker of gut inflammation however is not specific to Crohn’s disease (CD) or ulcerative colitis (UC) alone. Volatile organic compounds (VOCs) were shown to have potential in IBD diagnosis.

Areas covered: This systematic review aimed to examine the next-generation diagnosis of IBD in adults and children using VOCs. An in-depth literature-based search of current clinical studies of VOCs in the diagnosis of IBD was undertaken. Accuracy of IBD detection varied according to the technologies applied. Breath VOCs studies were pooled giving an overall sensitivity of 85% (95%CI: 79-89%) and specificity of 79% (95%CI 73-84%) whilst pooled fecal VOCs studies revealed a sensitivity of 87% (95%CI 77-93%) and specificity of 91% (95%CI 82-96%). Studies were limited by the variance of techniques applied in VOCs detection and the absence of well-designed longitudinal studies.

Expert opinion: VOCs can be consistently and effectively detected in urine, breath, and stool in IBD patients. The sensitivity of breath VOCs in detecting IBD was comparable to feces. However, optimal VOCs detection methodology and biological sampling still need to be standardized..

KEYWORDS:

• Inflammatory bowel disease
• diagnosis
• Crohn’s disease
• ulcerative colitis
• volatile organic compounds

Article highlights

• Faecal calprotectin (FCP) has a sensitivity of 93% and specificity of 94% in diagnosing bowel inflammation but it does not differentiate between Crohn’s disease (CD) or ulcerative colitis (UC)

• Breath VOCs studies using gas chromatography-ion mass spectrometry (GC-IMS) were pooled giving an overall sensitivity of 85% (95%CI: 79-89%) and specificity of 79% (95%CI 73-84%) for detecting IBD.

• Faecal VOCs studies using field asymmetric ion mobility spectroscopy (FAIMS) were pooled giving a sensitivity of 87% (95%CI 77-93%) and specificity of 91% (95%CI 82-96%)

• There are several VOCs described in the literature and appear dependant on the type of biological sample and methodology applied.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organisation or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded