The utility of faecal calprotectin to predict post-operative recurrence in Crohńs disease

Fecal calprotectin from ileostomy output in patients with Crohn's disease

BACKGROUND

Fecal calprotectin (FC) is a reliable biomarker widely used for assessing disease activity and postoperative monitoring in patients with Crohn's disease (CD); however, its efficacy in patients with an ileostomy is poorly understood. Our study evaluated whether FC from the ileostomy output can be used to predict postoperative small bowel inflammation in patients with CD.

METHODS

Data from patients with CD and an ileostomy who had undergone FC measurement between January 1, 2015, and December 30, 2022, were analyzed retrospectively. Patients were enrolled in the study if they had undergone FC tests with concurrent imaging and/or endoscopic studies, facilitating comparison between FC tests and imaging and/or endoscopic examinations. FC measured with the point-of care (POC) test was denoted as FC-POCT, and that measured using the enzyme-linked immunosorbent assay (ELISA) was denoted as FC-ELISA.

RESULTS

This study analyzed 101 patients and 224 FC test results. FC concentration differed significantly in patients with signs of small bowel inflammation on imaging and/or ileoscopy compared with those in remission (FC-POCT: median 191.0 µg/g; interquartile range [IQR], 94.6-499.0 µg/g vs. 29.9 µg/g; IQR, 29.9-50.0 µg/g; P < 0.001; FC-ELISA: median 252.5 µg/g; IQR, 118.5-911.0 µg/g vs. 16.8 µg/g, IQR, 8.2-33.0 µg/g; P < 0.001). The optimal cutoff value for FC-POCT and FC-ELISA to distinguish between small bowel inflammation and remission was 63.3 µg/g (area under the curve [AUC], 0.90; 95% confidence interval [CI], 0.88-0.97) and 40.1 µg/g (AUC, 0.89; 95% CI, 0.79-0.99), respectively. We also compared the diagnostic accuracy between the POC and ELISA testing methods and found no statistically significant difference (P = 0.692).

CONCLUSIONS

FC from the ileostomy output is a valuable biomarker with high sensitivity and specificity for monitoring small bowel inflammation in postoperative patients with CD and an ileostomy.

Fecal Calprotectin for the Diagnosis and Management of Inflammatory Bowel Diseases

Calprotectin is a heterodimeric calcium- and zinc-binding protein mainly derived from the cytoplasm of neutrophils that has direct antimicrobial functions and a role in the regulation of the innate immune response. It can be found in various biological compartments, in particular, the stool, with concentrations related to the level of mucosal inflammation. The measurement of fecal calprotectin has thus been recognized as a useful surrogate marker to distinguish patients with inflammatory bowel disease from those with irritable bowel syndrome. Moreover, it allows the monitoring of intestinal inflammation with a high negative predictive value, making it possible to exclude the diagnosis of inflammatory bowel disease for symptomatic patients. It also shows high sensitivity for the identification of patients requiring additional examinations for diagnosis, such as colonoscopy, and the evaluation of therapeutic responses, providing evidence of relapse or mucosal healing, which can lead to the intensification or reduction of treatment. As calprotectin levels are a measure of mucosal inflammation, high fecal concentrations are also found in other diseases with an inflammatory component, such as infectious enteritis or colorectal cancer. Interpretation of the concentration must therefore always take into account the clinical history and symptoms specific to each patient.

Advances in the Comprehensive Management of Postoperative Crohn's Disease

Patients with postoperative Crohn's disease are difficult to manage because of their risk of experiencing a more severe course, multiple symptom confounders, and poor sensitivity of symptomatic remission to rule out intestinal inflammation. In this group, data are lacking on biologic therapeutic efficacy, and recommendations are lacking for those with multiple medication failures. Novel noninvasive testing can simultaneously exclude alternate causes of symptoms (serum C4, fecal fat, small intestinal bowel overgrowth breath testing) and assess intestinal inflammation (fecal calprotectin, endoscopic healing index). In addition, endoscopy-based disease activity assessment and management are required. Endoscopy should be performed within 6 months of surgery, and aggressive disease activity monitoring can be considered with colonoscopy every 1-2 years subsequently to ensure late recurrence is detected. Patients with multiple resections should be screened for short bowel syndrome. Predictive biomarkers are needed to guide medication selection in this high-risk population. Postoperative prophylactic biologic therapy is prudent for patients with preoperative biologic failure. However, there are no high-quality data to guide which agent should be selected. Selecting biologics with an alternative mechanism of action in those who had failed a biologic with adequate drug concentrations and selection of different agents in those with previous intolerance are reasonable. Significantly more study is required to assess the efficacy of therapies in this setting.

Non-invasive Serological Monitoring for Crohn's Disease Postoperative Recurrence

INTRODUCTION

Crohn's disease recurs after intestinal resection. This study evaluated accuracy of a new blood test, the Endoscopic Healing Index [EHI], in monitoring for disease recurrence.

METHODS

Patients enrolled in the prospective POCER study [NCT00989560] underwent a postoperative colonoscopic assessment at 6 [2/3 of patients] and 18 months [all patients] following bowel resection, using the Rutgeerts score [recurrence ≥i2]. Serum was assessed at multiple time points for markers of endoscopic healing using the EHI, and paired with the Rutgeerts endoscopic score as the reference standard.

RESULTS

A total of 131 patients provided 437 serum samples, which were paired with endoscopic assessments available in 94 patients [30 with recurrence] at 6 months and 107 patients [44 with recurrence] at 18 months. The median EHI at 6 months was significantly lower in patients in remission [Rutgeerts <i2] than those with recurrence; p = 0.033. The area under the receiver operating curve [AUROC] for EHI to detect recurrence at 6 months was comparable to that of faecal calprotectin [0.712 vs 0.779, p = 0.414]. EHI of <20 at 6 months had a negative predictive value of 75.7% (95% confidence interval [CI] 58.8-88.2), and sensitivity of 70% [95% CI 50.6-85.3] for detecting recurrence. Combining all time points, an EHI <20 had a negative predictive value of 70.3%. Changes in EHI significantly associated with changes in Rutgeerts scores over the 18 months.

CONCLUSIONS

The non-invasive multi-marker EHI has sufficient accuracy to be used to monitor for postoperative Crohn's disease recurrence. A monitoring strategy that combines EHI with ileocolonoscopy, with or without faecal calprotectin, should now be prospectively tested.

Global Studies of Using Fecal Biomarkers in Predicting Relapse in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract mainly comprising two forms including Crohn's disease (CD) and ulcerative colitis (UC). IBD is a lifelong relapsing remitting disease and relapses occur at random patterns which are unpredictable. Fecal biomarkers have been increasingly used to assess disease activity in IBD due to their positive correlations with intestinal inflammation. Recent studies have also assessed the use of fecal biomarkers in predicting relapse and post-operative recurrence. This review provides information from global studies of using fecal calprotectin, lactoferrin and S100A12 to predict relapse in IBD. Strategies for further studies and the use of these fecal biomarkers for personalized management in IBD are also discussed.

The prevention and management of Crohn's disease postoperative recurrence: results from the Y-ECCO/ClinCom 2019 Survey

BACKGROUND

Prevention and management of postoperative recurrence (POR) is a controversial field in Crohn's disease. The aim of this survey was to report common practice in real-life settings.

METHODS

An 11-question survey was distributed among gastroenterologists attending the 14th European Crohn's and Colitis Organisation (ECCO) congress.

RESULTS

Postoperative endoscopy to assess recurrence was routinely performed within 12 months by 87% of respondents. Forty-six percent of clinicians reported to maintain endoscopic assessment in routine follow-up even after first negative colonoscopy. Most respondents (60%) considered starting postoperative immunoprophylaxis in naïve patients if one or more known risk factors were present. The number of risk factors was an important driver for prescribing biologics over immunosuppressants for 60% of respondents.In case of fistulizing phenotype, perianal disease, or concomitant colonic involvement, the majority of physicians reported to start an immediate prophylaxis in 85, 98 and 88% of patients, respectively. A significant percentage of clinicians were more prone to an endoscopy-driven treatment in long-standing disease after failure of thiopurines (51%) and elderly (43%).

CONCLUSION

Endoscopy within the first year after surgery to assess POR has become routine in most centres. The high rate of early prophylaxis with expensive biologics despite missing solid evidence highlights the need for more randomized trials.

Systematic Review and External Validation of Prediction Models Based on Symptoms and Biomarkers for Identifying Endoscopic Activity in Crohn's Disease

BACKGROUND & AIMS

Endoscopic healing, an important target of treatment for Crohn's disease (CD), requires ileocolonoscopy, which is costly and burdensome. We investigated whether published noninvasive models (based on symptoms and biomarkers) to evaluate CD activity have sufficient accuracy to replace ileocolonoscopy.

METHODS

We performed a systematic review of published noninvasive diagnostic models to evaluate CD activity that used endoscopic features of activity (endoscopic activity) or healing as the reference standard. We externally validated these models for the outcome endoscopic activity (CD endoscopic index of severity scores, ≥3) using data from the a randomized controlled trial investigating tailored treatment with infliximab for active luminal Crohn's disease (TAILORIX) study (346 ileocolonoscopies in 155 patients) and the Utrecht Activity Index (UAI) study (93 ileocolonoscopies in 82 patients). We calculated the area under the receiver operating characteristic curves (AUROCs) for the models using data from these studies, and compared the performance of these models against measurements of fecal calprotectin (FC) and C-reactive protein (CRP).

RESULTS

We screened 5303 articles and identified 27 models (from 21 studies) for our analysis. Seven models could be validated externally; in the TAILORIX data set, these models identified patients with endoscopic activity with AUROC values ranging from 0.61 (95% CI, 0.51-0.70) to 0.81 (95% CI, 0.76-0.86). In this data set, the AUROC value for FC concentration was 0.79 (95% CI, 0.74-0.85) and the AUROC value for CRP level was 0.72 (95% CI, 0.66-0.77). The AUROC values for the validation in the UAI data set were similar. In the TAILORIX and/or UAI data set, 4 of the 7 models, as well as the FC and CRP assays, were able to identify patients with endoscopic activity with positive predictive values of 90% or more. Two of the 7 models (but not the FC or CRP values) identified patients without endoscopic activity with a negative predictive value (NPV) of 90% or more, leading to correct prediction of endoscopic healing in 3.2% to 11.3% of all patients. For example, applying the Herranz-Bachiller model (1 of 7 models) at a NPV of 92.1% and a positive predictive value of 91.9% correctly identified 35.7% of all patients in whom ileocolonoscopy could be avoided for expected endoscopic activity or healing but incorrectly identified 3.2% of all patients. Most ileocolonoscopies (66.5% in TAILORIX and 72.6% in the UAI of all ileocolonoscopies) could be avoided correctly based on concentrations of FC of 100 μg/g or less and 250 μg/g or higher. However, using this range of FC concentrations to identify patients who do not require ileocolonoscopy caused 18.7% of all patients in the TAILORIX cohort and 19.8% of all patients in the UAI cohort to be predicted incorrectly to have endoscopic activity or healing.

CONCLUSIONS

In a systematic review and external validation of noninvasive models to identify patients with endoscopic activity of CD, we found only 2 of 7 models evaluated to have NPVs of 90% or more, however, leading to correctly predicted EH in only a small proportion of patients. Ileocolonoscopy therefore remains the mainstay to evaluate CD mucosal disease activity and healing.

Postoperative Crohn's disease management

PURPOSE OF REVIEW

Despite multiple advances in the medical treatment of Crohn's disease, it is recognized that a significant proportion of patients will ultimately require surgical resection at some point during their disease course. This review focuses on the postoperative management of patients with Crohn's disease, with the goal of preventing endoscopic and clinical recurrence, and future surgery.

RECENT FINDINGS

Surgery is an integral part of the multidisciplinary approach to the management of patients with Crohn's disease. Recent literature and guidelines have focused on a standardized and evidence-based approach to the management of patients in the postoperative setting. This approach should utilize risk stratification at the time of surgery, initiation of appropriate therapy among high-risk patients, and objective evaluation in the postoperative period, including ileocolonoscopy at 6-12 months after a surgical resection.

SUMMARY

A standardized approach to the postoperative management of patients with Crohn's disease is critical. Identifying those patients at high-risk for endoscopic and clinical recurrence is essential, as these patients will likely require early medical therapy. While novel objective assessments are emerging, all patients should undergo ileocolonoscopy at 6-12 months and further decision making should be based on the presence of endoscopic recurrence.

Is fecal calprotectin an accurate marker in the management of Crohn's disease?

Although lacking validated cutoff values, fecal calprotectin (FC), besides C-reactive protein, is considered the standard test for assessing disease activity in Crohn's disease (CD). The aim of the present review is to provide a general overview of the literature addressing the role of FC in the clinical and endoscopic assessment of disease activity in CD, seeking correlations with capsule endoscopy, response to therapy, prediction of relapse, and postoperative recurrence. A systematic search of the literature up to September 2019 was performed using Medline, Embase, and the Cochrane Library. Only papers written in English concerning FC in adult patients affected by CD were included. Pediatric studies, in vitro studies, animal studies, studies on blood/serum samples, and studies analyzing FC in ulcerative colitis or in both CD and ulcerative colitis were excluded. Out of 713 citations, 65 eligible studies were identified. FC showed high accuracy in the assessment of intestinal inflammation and response to therapy, in particular in colonic disease, thus proving a good surrogate marker for these aims. FC is useful in identifying patients at high risk for endoscopic relapse or postoperative recurrence, for optimizing or downstage therapy. Unfortunately, FC performs less well in small bowel CD. FC is an effective fecal marker in the management of CD patients, optimizing the use of endoscopic procedures. Owing to its diagnostic accuracy, FC may represent a cornerstone of the "treat-to-target" management strategy of CD patients.

Prediction of treatment outcome and relapse in inflammatory bowel disease

Prediction of treatment outcome and clinical relapse in patients with inflammatory bowel disease (IBD), either ulcerative colitis (UC) or Crohn's disease (CD), is particularly important because therapeutics for IBD are not always effective and patients in remission could frequently relapse. Because undergoing endoscopy for the purpose is sometimes invasive and burdensome to patients, the performance of surrogate biomarkers has been investigated. Areas covered: We particularly featured the performance of patient symptoms, blood markers including C-reactive protein (CRP), fecal markers including fecal calprotectin (Fcal) and fecal immunochemical test (FIT) for prediction of endoscopic mucosal healing (MH) and prediction of relapse. Studies of other modalities and therapeutic drug monitoring (TDM) have also been explored. Expert opinion: Meticulous evaluation of patient symptoms could be predictive for MH in UC. CRP and Fcal may be accurate in prediction of MH of CD when MH is evaluated throughout the entire intestine including the small bowel. Repeated measurements of fecal markers including Fcal and FIT in patients with clinical remission would raise predictability of relapse. Prediction of treatment outcome by monitoring with blood markers including CRP, fecal markers including Fcal, and TDM has frequently been performed in recent clinical trials and shown to be effective.

Fecal calprotectin is not superior to serum C-reactive protein or the Harvey-Bradshaw index in predicting postoperative endoscopic recurrence in Crohn's disease

BACKGROUND

Fecal calprotectin (FC) is a widely used noninvasive marker of gut inflammation that is associated with endoscopic severity in Crohn's disease (CD). However, FC has been inconsistent in predicting postoperative recurrence of CD, and its utility in the postoperative setting remains unclear.

MATERIALS AND METHODS

Blood and fecal samples were collected in consecutively recruited patients with CD who had undergone ileocolonic resection and required a colonoscopy to assess postoperative recurrence, as defined by the Rutgeerts score (RS).

RESULTS

A total of 86 patients were prospectively recruited at five centers. Overall, 49 (57%) had CD recurrence (RS≥i2). FC concentrations trended to increase with RS severity; FC median (interquartile range) was significantly higher in patients with endoscopic recurrence than those in endoscopic remission [172.5 (75-375) vs. 75 (36.5-180.5) μg/g, respectively]. The same occurred for C-reactive protein (CRP) [0.5 (0.1-0.95) vs. 0.1 (0.02-0.27)] mg/dl and the Harvey-Bradshaw index (HBI) [4 (2-7) vs. 1 (0-3.5)]. The three variables significantly correlated. The area under the curve to discriminate between patients in endoscopic remission and recurrence was 0.698 for FC, with 62 μg/g being the optimal cut-off point. This indicated FC would have 85.7% sensitivity and 45.9% specificity in detecting any recurrence, having positive predictive value and negative predictive value of 67.7 and 70.8%, respectively. Area under the curve for CRP and HBI were both 0.710. The combination of CRP and HBI provided a positive predictive value 95.7 and a diagnostic odds ratio of 30.8.

CONCLUSION

FC is not better than CRP combined with HBI to predict endoscopic postoperative recurrence of CD.

From bench to bedside: Fecal calprotectin in inflammatory bowel diseases clinical setting

Fecal calprotectin (FC) has emerged as one of the most useful tools for clinical management of inflammatory bowel diseases (IBD). Many different methods of assessment have been developed and different cut-offs have been suggested for different clinical settings. We carried out a comprehensive literature review of the most relevant FC-related topics: the role of FC in discriminating between IBD and irritable bowel syndrome (IBS) and its use in managing IBD patients In patients with intestinal symptoms, due to the high negative predictive value a normal FC level reliably rules out active IBD. In IBD patients a correlation with both mucosal healing and histology was found, and there is increasing evidence that FC assessment can be helpful in monitoring disease activity and response to therapy as well as in predicting relapse, post-operative recurrence or pouchitis. Recently, its use in the context of a treat-to-target approach led to a better outcome than clinically-based therapy adjustment in patients with early Crohn’s disease. In conclusion, FC measurement represents a cheap, safe and reliable test, easy to perform and with a good reproducibility. The main concerns are still related to the choice of the optimal cut-off, both for differentiating IBD from IBS, and for the management of IBD patients.

Fecal calprotectin for detection of postoperative endoscopic recurrence in Crohn's disease: systematic review and meta-analysis

BACKGROUND

Anastomotic recurrence is frequent in patients with Crohn's disease (CD) following ileocecal resection. The degree of endoscopic recurrence, quantified by the Rutgeerts score (RS), correlates with risk of clinical and surgical recurrence. Several studies demonstrate the accuracy of fecal calprotectin (FC) for detection of endoscopic recurrence, however the optimal threshold FC value remains to be established. The aim of our meta-analysis was to evaluate the accuracy of common FC cut-offs for detection of endoscopic recurrence.

METHODS

We performed a systematic literature search for studies evaluating postoperative recurrence in CD which reported RS and FC levels. Endoscopic recurrence was defined as RS = 2-4 (or RS ⩾ 2). We calculated pooled diagnostic sensitivity, specificity, diagnostic odds ratio (DOR) and constructed summary receiver operating characteristic (SROC) curves for each available FC cut-off value.

RESULTS

A total of 54 studies were retrieved; 9 studies were eligible for analysis. Diagnostic accuracy was calculated for FC values of 50, 100, 150 and 200 µg/g. A significant threshold effect was observed for all FC values. The optimal diagnostic accuracy was obtained for FC value of 150 µg/g, with a pooled sensitivity of 70% [95% confidence interval (CI) 59-81%], specificity 69% (95% CI 61-77%), and DOR 5.92 (95% CI 2.61-12.17). The area under the SROC curve was 0.73.

CONCLUSION

FC is an accurate surrogate marker of postoperative endoscopic recurrence in CD patients. The FC cut-off 150 μg/g appears to have the best overall accuracy. Serial FC evaluations may eliminate or defer the need for colonoscopic evaluation in up to 70% of postoperative CD patients.

Monitoring and detection of disease recurrence after resection for Crohn's disease: the role of non-invasive fecal biomarkers

Ileocolonoscopy is the gold standard for the diagnosis and assessment of postoperative recurrence in Crohn's disease (CD). Nevertheless, endoscopy is time-consuming and invasive. A minimally invasive and simple screening test would improve patient adherence to examination and provide greater clinical benefit. A number of fecal biomarkers have been evaluated for their utility for the diagnosis and monitoring of inflammatory bowel disease as alternative tests to endoscopy. Area covered: In this review, we focused on the utility of fecal biomarkers in the management of postoperative CD. Our major endeavor was to present an evidence-based assessment of the results of clinical trials on the available data. A literature search was conducted using the Medline. Expert commentary: Calprotectin and lactoferrin, both neutrophil-derived proteins, are the two most frequently used fecal biomarkers in clinical trials and practice. Several studies evaluated the role of these fecal biomarkers in patients with postoperative CD. These studies suggest that fecal calprotectin, and to a lesser degree lactoferrin, are useful in assessing endoscopic severity and in predicting future clinical recurrence after resection for CD. However, large scale, well-designed studies are necessary to rigorously evaluate the role of fecal biomarkers in postoperative CD.

Risk factors for postoperative recurrence of Crohn's disease with emphasis on surgical predictors

Intestinal resection for Crohn’s disease is not curative and postoperative recurrence rates remain high. Early detection of indices associated with recurrence and risk stratification are fundamental for the postoperative management of patients. Early endoscopy at 6-12 months is the “gold standard” procedure, whereas other modalities such as fecal calprotectin and imaging techniques can contribute to the diagnosis of recurrence. The purpose of this review is to summarize current data regarding risk factors correlated with postoperative relapse. Smoking is a well-established, modifiable risk factor. There are sufficient data that correlate penetrating disease, perianal involvement, extensive resections, prior surgery, histological features (plexitis and granulomas), and improper management after resection with high rates for recurrence. The literature provides conflicting data for other possible predictors, such as age, sex, family history of inflammatory bowel disease, location of disease, strictureplasties, blood transfusions, and postoperative complications, necessitating further evidence. On the other hand, surgical factors such as anastomotic configuration, open or laparoscopic approach, and microscopic disease at specimen margins when macroscopic disease is resected, seem not to be related with an increased risk of recurrence. Further recognition of histological features as well as gene-related factors are promising fields for research.

An update on diagnostic and prognostic biomarkers in inflammatory bowel disease

Diagnosis of the chronic inflammatory bowel diseases relies upon initial recognition of an inflammatory condition, followed by definitive endoscopic, histological and radiological investigations. Various biomarkers are available to assist with initial elucidation of an inflammatory process: these also have important roles after diagnosis in monitoring and ongoing assessment of progress. Areas covered: Various inflammatory markers, serological tests and genetic analyses may be helpful in predicting the course of disease in the coming months. This review provides an update on the current understanding and knowledge about these markers. It also highlights key gaps and identifies aspects that require further study. Expert commentary: Our current approach to the application of non-invasive biomarkers is rudimentary. Further work is required to elucidate the roles of the various markers.

Validation of a care pathway for the use of faecal calprotectin in monitoring patients with Crohn's disease

INTRODUCTION

We have previously published an evidence-based care pathway for the use of faecal calprotectin (FC) to monitor patients with Crohn's disease established on therapy. Patients are treated as low, intermediate or high risk of continuing Crohn's disease activity based on their FC, whatever their phenotype and surgical status are. Low-risk patients (FC <100 µg/g) are offered 12 monthly follow-ups or step down of therapy if asymptomatic or initial expectant symptomatic treatment. Intermediate-risk patients (FC 100-250 µg/g) are reviewed at 6 months with a repeat FC. High-risk patients (two consecutive FCs >250 µg/g) are flagged up to the responsible clinician as likely having an active Crohn's disease.

METHODS

To validate this care pathway over a 2-year period, by determining its negative predictive value (NPV) and positive predictive value (PPV).

RESULTS

123 patients were managed by means of the care pathway for a mean of 24.4 months. The NPV and PPV were 0.97 (CI 0.93 to 0.98) and 0.85 (CI 0.80 to 0.94), respectively (sensitivity: 0.92 (0.83 to 0.96) and specificity: 0.95 (0.92 to 0.98)). Importantly 69% of patients with FC >250 µg/g were in clinical remission, the care pathway identifying patients who would benefit from presymptomatic disease modification.

CONCLUSIONS

This validation of a pragmatic clinical care pathway demonstrates a safe and effective mechanism by which to use FC to monitor risk of disease activity in patients with Crohn's disease established on therapy. It provides a framework for prioritising follow-up and for identifying patients at risk of continuing disease activity or those in whom therapy could be stepped down.

Fecal biomarkers in inflammatory bowel disease: how, when and why?

Over the last thirty years knowledge on fecal biomarkers (FM) has substantially increased. Nowadays these non-invasive inflammation markers are used in the daily management of inflammatory bowel disease (IBD). The interest in investigating FM was motivated by the need of a simple, quick, disposable and less invasive marker of disease activity, which might remove the need for endoscopy when following up with patients. Areas covered: Current literature was reviewed for articles regarding the role of FM in IBD diagnosis, activity, flare prediction, medication and surgical treatment response as well as how FM may differ in adult and paediatric IBD patient populations. Expert commentary: Although FM is relevant in IBD patient follow-up, there isn't enough data regarding FM reference values for different ages, different disease subtypes, disease localization/extension or response to therapy. Serial measurements of FM for each patient may be useful in accessing relapse in most patients. FM presented more consistent results when used as a predictive tool of relapse after ileocecal surgery in Crohn's disease. Ongoing research will clarify FM role in decision-making IBD daily practice.