Irritable bowel syndrome is a disorder diagnosed on symptom-based criteria without inclusion of any objective parameter measurable by known diagnostic methods. Heterogeneity of the disorder and overlapping with more serious organic diseases increase uncertainty for the physicians work and increase the cost of confirming the diagnosis. This paper is an attempt to summarize the efforts to find adequate biomarkers for irritable bowel syndrome, which should shorten the time to diagnosis and reduce the cost. Most of the reviewed papers were observational studies from secondary care institutions. Since publication of the Rome III criteria in 2006, most recent studies use these for the recruitment of IBS patients. This is a positive step forward as future studies should use the same criteria, facilitating comparison of their results. Among the studied biomarkers, most evidence is provided for fecal calprotectin. Cutoff values for fecal calprotectin have still to be investigated prior to inclusion in the irritable bowel syndrome diagnostic algorithm.

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder with a severe impact on quality of life (QoL). We explored the relationship of a visual measure of suffering, the PRISM-RII, with quality of life (QoL) and anxiety measures in IBS patients. Participants were 44 IBS patients who completed several questionnaires and kept a symptom diary for two weeks. The measures used were PRISM-RII (self-illness separation (SIS); illness perception measure (IPM)); IBS-36 (IBS health related QoL); SF-36 (physical and mental health related QoL); State-Trait Anxiety Inventory (STAI-T); Visceral Sensitivity Index (VSI; GI-specific anxiety); and a symptom diary. SIS was negatively correlated to VSI, while IPM was negatively correlated to SIS and the physical component of SF-36 and positively to VSI and symptom severity. We found significant differences between participants who perceive their illness as small and those who perceive it as medium in SIS, symptom severity, VSI, and the mental component of SF-36. Participants, who perceived their illness as small, represented their illness as more distant, showed lower average symptom severity, and had lower GI-specific anxiety and higher QoL. The results indicate that IPM and SIS can be useful in discriminating patients with more prominent psychological difficulties and QoL impairment.

Irritable bowel syndrome (IBS) has a complex aetiology involving biological and psychological alterations. Among others, stress seems to be a relevant factor for IBS symptom onset and exacerbation. Affective changes can be related to symptom severity and stressful experiences and may be valuable for therapeutic purposes. The aim of this study was to examine temporal dynamics of affect, stress, and symptom severity (specifically abdominal pain) in a sample of IBS patients. Thirty-two outpatients kept a diary with a set of short questionnaires (Affect scale, Symptom severity scale, and Daily stress measure) once a day, in the evening, for 14 days. Abdominal pain was modeled as a function of between-person, concurrent and lagged within-person effect of stress and affect controlling for autoregressive pain effects. Positive and negative affect exhibited concurrent effects on abdominal pain while stress did not. Daily variation in positive affect was associated with a decrease in pain while the opposite was true for negative affect. Positive and negative affect models explained over 40% of the variation in daily abdominal pain. Even though the models had a good fit, the amount of variance explained by positive and negative affect alone was relatively small (~7%) with high interindividual heterogeneity. It seems that day-to-day stress variations do not have a direct impact on abdominal pain, while affective dynamics appear closely related to pain variations.