Perinuclear antineutrophil cytoplasmic autoantibodies and anti-Saccharomyces cerevisiae antibodies as serological markers are not specific in the identification of Crohn's disease and ulcerative colitis

Canine chronic enteropathy—Current state-of-the-art and emerging concepts

Over the last decade, chronic inflammatory enteropathies (CIE) in dogs have received great attention in the basic and clinical research arena. The 2010 ACVIM Consensus Statement, including guidelines for the diagnostic criteria for canine and feline CIE, was an important milestone to a more standardized approach to patients suspected of a CIE diagnosis. Great strides have been made since understanding the pathogenesis and classification of CIE in dogs, and novel diagnostic and treatment options have evolved. New concepts in the microbiome-host-interaction, metabolic pathways, crosstalk within the mucosal immune system, and extension to the gut-brain axis have emerged. Novel diagnostics have been developed, the clinical utility of which remains to be critically evaluated in the next coming years. New directions are also expected to lead to a larger spectrum of treatment options tailored to the individual patient. This review offers insights into emerging concepts and future directions proposed for further CIE research in dogs for the next decade to come.

Development of an indirect immunofluorescence based assay for diagnosis of ulcerative colitis in Indian population

The prevalence of Ulcerative Colitis (UC), once thought to be negligible, has increases exponentially in the Indian population. The development of novel, cost effective and time efficient Indirect Immunofluorescence (IIF) based assay for detection of anti-neutrophil cytoplasmic antibodies (ANCA) and diagnosis of UC in the Indian population is discussed. A novel IIF based assay was developed using intact nuclei from human neutrophils to detect atypical p-ANCA in patients suffering from UC. Sera from 45 patients diagnosed with UC, 45 healthy controls and one related disease control were tested using a novel UC-ANCA assay and validated by commercially available ANCA IIF assay. Prevalence of ANCA amongst UC patients in the Indian population was determined. Atypical p-ANCA was detected in 86.6% of the patients using the UC-ANCA assay as compared to 71.1% using the commercial ANCA assay. The validation of UC-ANCA assay with a commercially available ANCA IIF assay resulted in higher sensitivity. The UC-ANCA assay proved to be not only enhanced in terms of performance but also comparatively economical and rapid. The novel UC-ANCA assay may prove to be very useful in identification and differentiation of UC patients from typical ANCA positive subjects suffering from other autoimmune diseases at one tenth the cost of clinically available ANCA IIF tests which will immensely benefit the cost constrained diagnostic field of developing countries.

Crohn's Disease: Evolution, Epigenetics, and the Emerging Role of Microbiome-Targeted Therapies

Crohn's disease (CD) is a chronic, systemic, immune-mediated inflammation of the gastrointestinal tract. Originally described in 1932 as non-caseating granulomatous inflammation limited to the terminal ileum, it is now recognized as an expanding group of heterogeneous diseases defined by intestinal location, extent, behavior, and systemic extraintestinal manifestations. Joint diseases, including inflammatory spondyloarthritis and ankylosing spondylitis, are the most common extraintestinal manifestations of CD and share more genetic susceptibility loci than any other inflammatory bowel disease (IBD) trait. The high frequency and overlap with genes associated with infectious diseases, specifically Mendelian susceptibility to mycobacterial diseases (MSMD), suggest that CD may represent an evolutionary adaptation to environmental microbes. Elucidating the diversity of the enteric microbiota and the protean mucosal immune responses in individuals may personalize microbiome-targeted therapies and molecular classifications of CD. This review will focus on CD's natural history and therapies in the context of epigenetics, immunogenetics, and the microbiome.

Identification of disease-specific motifs in the antibody specificity repertoire via next-generation sequencing

Disease-specific antibodies can serve as highly effective biomarkers but have been identified for only a relatively small number of autoimmune diseases. A method was developed to identify disease-specific binding motifs through integration of bacterial display peptide library screening, next-generation sequencing (NGS) and computational analysis. Antibody specificity repertoires were determined by identifying bound peptide library members for each specimen using cell sorting and performing NGS. A computational algorithm, termed Identifying Motifs Using Next- generation sequencing Experiments (IMUNE), was developed and applied to discover disease- and healthy control-specific motifs. IMUNE performs comprehensive pattern searches, identifies patterns statistically enriched in the disease or control groups and clusters the patterns to generate motifs. Using celiac disease sera as a discovery set, IMUNE identified a consensus motif (QPEQPF[PS]E) with high diagnostic sensitivity and specificity in a validation sera set, in addition to novel motifs. Peptide display and sequencing (Display-Seq) coupled with IMUNE analysis may thus be useful to characterize antibody repertoires and identify disease-specific antibody epitopes and biomarkers.

Asia Pacific Consensus Statements on Crohn's disease. Part 1: Definition, diagnosis, and epidemiology: (Asia Pacific Crohn's Disease Consensus--Part 1)

Inflammatory bowel disease (IBD) was previously thought to be rare in Asia, but emerging data indicate rising incidence and prevalence of IBD in the region. The Asia Pacific Working Group on Inflammatory Bowel Disease was established in Cebu, Philippines, at the Asia Pacific Digestive Week conference in 2006 under the auspices of the Asian Pacific Association of Gastroenterology with the goal of developing best management practices, coordinating research, and raising awareness of IBD in the region. The consensus group previously published recommendations for the diagnosis and management of ulcerative colitis with specific relevance to the Asia-Pacific region. The present consensus statements were developed following a similar process to address the epidemiology, diagnosis, and management of Crohn's disease. The goals of these statements are to pool the pertinent literature specifically highlighting relevant data and conditions in the Asia-Pacific region relating to the economy, health systems, background infectious diseases, differential diagnoses, and treatment availability. It does not intend to be all comprehensive and future revisions are likely to be required in this ever-changing field.

Review article: breath analysis in inflammatory bowel diseases

BACKGROUND

There is an urgent need for cheap, reproducible, easy to perform and specific biomarkers for diagnosis, differentiation and stratification of inflammatory bowel disease (IBD) patients. Technical advances allow for the determination of volatile organic compounds in the human breath to differentiate between health and disease.

AIM

Review and discuss medical literature on volatile organic compounds in exhaled human breath in GI disorders, focusing on diagnosis and differentiation of IBD.

METHODS

A systematic search in PubMed, Ovid Medline and Scopus was completed using appropriate keywords. In addition, a bibliography search of each article was performed.

RESULTS

Mean breath pentane, ethane, propane, 1-octene, 3-methylhexane, 1-decene and NO levels were elevated (P < 0.05 to P < 10(-7)) and mean breath 1-nonene, (E)-2-nonene, hydrogen sulphide and methane were decreased in IBD compared to healthy controls (P = 0.003 to P < 0.001). A combined panel of 3 volatile organic compounds (octene, (E)-2-nonene and decene) showed the best discrimination between paediatric IBD and controls (AUC 0.96). Breath condensate cytokines were higher in IBD compared to healthy individuals (P < 0.008). Breath pentane, ethane, propane, isoprene and NO levels correlated with disease activity in IBD patients. Breath condensate interleukin-1β showed an inverse relation with clinical disease activity.

CONCLUSIONS

Breath analysis in IBD is a promising approach that is not yet ready for routine clinical use, but data from other gastrointestinal diseases suggest the feasibility for use of this technology in clinical practice. Well-designed future trials, incorporating the latest breath detection techniques, need to determine the exact breath metabolome pattern linked to diagnosis and phenotype of IBD.

Diagnosis of inflammatory bowel disease: Potential role of molecular biometrics

Accurate diagnosis of predominantly colonic inflammatory bowel disease (IBD) is not possible in 30% of patients. For decades, scientists have worked to find a solution to improve diagnostic accuracy for IBD, encompassing Crohn's colitis and ulcerative colitis. Evaluating protein patterns in surgical pathology colectomy specimens of colonic mucosal and submucosal compartments, individually, has potential for diagnostic medicine by identifying integrally independent, phenotype-specific cellular and molecular characteristics. Mass spectrometry (MS) and imaging (I) MS are analytical technologies that directly measure molecular species in clinical specimens, contributing to the in-depth understanding of biological molecules. The biometric-system complexity and functional diversity is well suited to proteomic and diagnostic studies. The direct analysis of cells and tissues by Matrix-Assisted-Laser Desorption/Ionization (MALDI) MS/IMS has relevant medical diagnostic potential. MALDI-MS/IMS detection generates molecular signatures obtained from specific cell types within tissue sections. Herein discussed is a perspective on the use of MALDI-MS/IMS and bioinformatics technologies for detection of molecular-biometric patterns and identification of differentiating proteins. I also discuss a perspective on the global challenge of transferring technologies to clinical laboratories dealing with IBD issues. The significance of serologic-immunometric advances is also discussed.

Characteristics of inflammatory bowel disease serology in patients with indeterminate colitis

GOALS AND BACKGROUND

Inflammatory bowel disease (IBD) serology testing is often used in patients with indeterminate colitis (IC) to help distinguish between ulcerative colitis (UC) and Crohn's disease (CD). We investigated the performance of serology testing in predicting future diagnosis in this setting.

STUDY

This was an observational study of individuals with IC at a single center who underwent IBD serology testing [anti-Saccharomyces cerevisiae antibody (ASCA), perinuclear anti-neutrophil cytoplasmic antibody (pANCA), and anti-outer membrane porin C antibody (anti-OmpC)] and had at least 12 months follow-up from the time of serology test results.

RESULTS

A total of 117 individuals with IC and with 1-year follow-up data were enrolled. All IC patients had endoscopic and histologic evidence of colitis at enrollment. One year after serology testing, 58 (50%) individuals with IC were diagnosed with UC, 49 (42%) with CD, and 10 (9%) remained labeled with IC. The sensitivity/specificity of an initial positive pANCA for a subsequent diagnosis of UC was 78%/44%. For ASCA and anti-OmpC, the results were 18%/84% and 27%/75%, respectively, for a subsequent diagnosis of CD. A positive pANCA test was associated with a likelihood ratio (LR) of 1.4 [95% confidence interval (CI), 1.1-1.8] for a subsequent diagnosis of UC at 1 year. Neither positive ASCA (LR 1.1; 95% CI, 0.5-2.5) nor anti-OmpC (LR 1.1; 95% CI, 0.6-2.0) was associated with a subsequent diagnosis of CD in patients with IC.

CONCLUSIONS

The disease phenotype in the majority of individuals initially labeled with IC evolved to be more consistent with either UC or CD on follow-up. pANCA, ASCA, and anti-OmpC, individually, were of limited utility in predicting a patient's subsequent disease phenotype.

Proteomic patterns of colonic mucosal tissues delineate Crohn's colitis and ulcerative colitis

PURPOSE

Although Crohn's colitis (CC) and ulcerative colitis (UC) share several clinical features, they have different causes, mechanisms of tissue damage, and treatment options. Therefore, the accurate diagnosis is of paramount importance in terms of medical care. The distinction between CC/UC is made on the basis of clinical, radiologic, endoscopic, and pathologic interpretations but cannot be differentiated in up to 15% of inflammatory bowel disease patients. Correct management of this "indeterminate colitis" depends on the accuracy of future, and yet not known, destination diagnosis (CC/UC).

EXPERIMENTAL DESIGN

We have developed a proteomic methodology that has the potential to discriminate between UC/CC. The histologic layers of 62 confirmed UC/CC tissues were analyzed using MALDI-MS for proteomic profiling.

RESULTS

A Support Vector Machine algorithm consisting of 25 peaks was able to differentiate spectra from CC and UC with 76.9% spectral accuracy when using a leave-20%-out cross-validation. Application of the model to the entire dataset resulted in accurate classification of 19/26 CC patients and 36/36 UC patients when using a 2/3 correct cutoff. A total of 114 peaks were found to have Wilcoxin rank sum p-values of less than 0.05.

CONCLUSION AND CLINICAL RELEVANCE

This information may provide new avenues for the development of novel personalized therapeutic targets.

Perinuclear antineutrophil cytoplasmic autoantibodies in dogs infected with various vector-borne pathogens and in dogs with immune-mediated hemolytic anemia

OBJECTIVE

To determine the prevalence of perinuclear antineutrophil cytoplasmic autoantibodies (pANCA) in dogs with confirmed or suspected immune-mediated hemolytic anemia (IMHA) or dogs infected with various vector-borne pathogens, including Rickettsia rickettsii, Bartonella henselae, Bartonella vinsonii subsp berkhoffii, Ehrlichia canis, Borrelia burgdorferi, and Leishmania infantum.

ANIMALS

55 dogs with confirmed or suspected IMHA, 140 dogs seroreactive for vector-borne pathogens, and 62 healthy dogs and dogs seronegative for vector-borne pathogens.

PROCEDURES

Samples were allocated to subgroups on the basis of the health status of the dogs and the degree of seroreactivity against various vector-borne pathogens. Serum samples were tested retrospectively via indirect immunofluorescence assay to determine pANCA status.

RESULTS

26 of 55 (47%) dogs with confirmed or suspected IMHA and 67 of 140 (48%) dogs seroreactive for vector-borne pathogens had positive results when tested for pANCA. Serum samples with the highest antibody concentrations against L infantum antigen had the highest proportion (28/43 [65%]) that were positive for pANCA. One of 20 (5%) dogs seronegative for tick-borne pathogens and 8 of 22 (36%) dogs seronegative for L infantum had positive results for pANCA. One of 20 (5%) healthy dogs had serum antibodies against pANCA.

CONCLUSIONS AND CLINICAL RELEVANCE

pANCA were detected in a high percentage of dogs with IMHA and vector-borne infectious diseases. Therefore, pANCA may be a relatively nonspecific marker for dogs with inflammatory bowel disease, although they could represent a biomarker for immune-mediated diseases and infections.

Serological antibodies in inflammatory bowel disease: a systematic review

The diagnosis of inflammatory bowel disease (IBD) is traditionally based on a combination of clinical, endoscopic, histological, and radiological criteria. However, further testing is needed in cases of diagnostic uncertainty and in predicting disease course. This systematic review focuses on the potential for 10 serological antibodies to fill these roles: pANCA, ASCA, anti-OmpC, anti-CBir1, anti-I2, ALCA, ACCA, AMCA, anti-L, and anti-C. We discuss their prevalence in IBD and health; their role in disease diagnosis and risk stratification; their stability over time; their presence in unaffected relatives; their association with genetic variants; and differences across ethnic groups. Serological antibodies have some role in primary diagnosis and in differentiating between Crohn's disease and ulcerative colitis. In indeterminate colitis, preoperative measurement of serological antibodies can help to predict the likelihood of complications among patients undergoing pouch surgery. The combined presence and magnitude of a large panel of antibodies appear to be of value in predicting disease progression. There is currently insufficient evidence to recommend the use of antibody testing to predict responses to treatment or surgery in patients with IBD.

ASCA IgG and CBir antibodies are associated with the development of Crohn's disease and fistulae following ileal pouch-anal anastomosis

BACKGROUND

For ulcerative colitis (UC) patients undergoing ileal pouch-anal anastomosis (IPAA), postoperative complications include chronic pouchitis and development of Crohn's disease (CD) of the pouch.

AIMS

The aim of this study was to determine if serologic markers obtained postoperatively are associated with the development of complications in UC patients after IPAA.

METHODS

A retrospective chart review was conducted of UC patients with IPAA were tested for expression of serologic markers. Complications abstracted from medical records included postoperative fistula, CD of the pouch, chronic pouchitis, and diversion or excision of the pouch.

RESULTS

142 patients were enrolled, 44 of whom developed complications. Positive serologic profiles for ASCA IgG and anti-CBir1 markers were found to be associated with the development of any complication, (P = 0.017 and P = 0.002, respectively). A positive anti-CBir1 test was also found to be associated with CD of the pouch and/or fistula formation (P < 0.001). Similarly, both ASCA IgG and anti-CBir1 titers were significantly associated with postoperative IPAA complications (P = 0.034 and P = 0.001, respectively), and anti-CBir1 titers were associated with CD of the pouch and/or fistula formation (P < 0.001). Complications developed after a median follow-up of 216 months (range 1-264).

CONCLUSIONS

ASCA IgG and anti-CBir1 markers were associated with the development of complications after IPAA, specifically fistulae and/or CD of the pouch. The ability to identify patients at high risk for adverse outcomes may allow for early aggressive therapy, which may decrease the rate of pouch failure. A prospective study of patients with preoperative serology is ongoing.

Contribution of immunofluorescence to identification and characterization of antineutrophil cytoplasmic antibodies in inflammatory bowel disease

We evaluated the combined use of different fixatives for the identification of atypical perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) in patients with inflammatory bowel diseases (IBD) by indirect immunofluorescence (IIF). Sera from 59 ulcerative colitis (UC) and 37 Crohn's disease (CD) patients, and from 64 healthy controls were studied. The IIF on ethanol-, formalin-, and methanol-fixed neutrophils was used for the detection of ANCA. Enzyme linked immunosorbant assay (ELISA) was performed to identify the antigens recognized by ANCA. ANCAs were present in 35 of 59 (59.3%) UC patients and in 10 of 37 (27.02%) CD patients. Atypical p-ANCA positivity was strongly associated with UC disease (44.1% in UC vs. 8.1% in CD; p = 0.0002). The combined application of different fixatives contributed to make easy the differentiation between typical p-ANCA and atypical p-ANCA. Atypical p-ANCA determination appears to be a useful parameter for the distinction between UC and CD.

Circulating microRNA is a biomarker of pediatric Crohn disease

OBJECTIVE

The gold standard for the diagnosis and evaluation of Crohn disease (CD) is endoscopy/colonoscopy, although this is invasive, costly, and associated with risks to the patient. Recently, circulating microRNAs (miRNAs) have emerged as promising noninvasive biomarkers. Here, we examined the utility of serum miRNAs as biomarkers of CD in children.

PATIENTS AND METHODS

Studies were conducted using sera samples from patients with pediatric CD, healthy controls, and a comparison group of patients with pediatric celiac disease. Serum miRNA levels were explored initially using a microfluidic quantitative reverse transcription-polymerase chain reaction array platform. Findings were subsequently validated using quantitative reverse transcription-polymerase chain reaction in larger validation sample sets. The diagnostic utility of CD-associated serum miRNA was examined using receiver operating characteristic analysis.

RESULTS

A survey of miRNA levels in the sera of control and patients with CD detected significant elevation of 24 miRNAs, 11 of which were chosen for further validation. All of the candidate biomarker miRNAs were confirmed in an independent CD sample set (n = 46). To explore the specificity of the CD-associated miRNAs, they were measured in the sera of patients with celiac disease (n = 12); none were changed compared with healthy controls. Receiver operating characteristic analyses revealed that serum miRNAs have promising diagnostic utility, with sensitivities for CD above 80%. Significant decreases in serum miRNAs were observed in 24 incident patients with pediatric CD after 6 months of treatment.

CONCLUSIONS

The present study identifies 11 CD-associated serum miRNA with encouraging diagnostic potential. Our findings suggest serum miRNAs may prove useful as noninvasive biomarkers in CD.

Circulating microRNA is a biomarker of pediatric Crohn disease

OBJECTIVE

The gold standard for the diagnosis and evaluation of Crohn disease (CD) is endoscopy/colonoscopy, although this is invasive, costly, and associated with risks to the patient. Recently, circulating microRNAs (miRNAs) have emerged as promising noninvasive biomarkers. Here, we examined the utility of serum miRNAs as biomarkers of CD in children.

PATIENTS AND METHODS

Studies were conducted using sera samples from patients with pediatric CD, healthy controls, and a comparison group of patients with pediatric celiac disease. Serum miRNA levels were explored initially using a microfluidic quantitative reverse transcription-polymerase chain reaction array platform. Findings were subsequently validated using quantitative reverse transcription-polymerase chain reaction in larger validation sample sets. The diagnostic utility of CD-associated serum miRNA was examined using receiver operating characteristic analysis.

RESULTS

A survey of miRNA levels in the sera of control and patients with CD detected significant elevation of 24 miRNAs, 11 of which were chosen for further validation. All of the candidate biomarker miRNAs were confirmed in an independent CD sample set (n = 46). To explore the specificity of the CD-associated miRNAs, they were measured in the sera of patients with celiac disease (n = 12); none were changed compared with healthy controls. Receiver operating characteristic analyses revealed that serum miRNAs have promising diagnostic utility, with sensitivities for CD above 80%. Significant decreases in serum miRNAs were observed in 24 incident patients with pediatric CD after 6 months of treatment.

CONCLUSIONS

The present study identifies 11 CD-associated serum miRNA with encouraging diagnostic potential. Our findings suggest serum miRNAs may prove useful as noninvasive biomarkers in CD.

Pitfalls and progress in the diagnosis and management of canine inflammatory bowel disease

Inflammatory bowel disease (IBD) is the collective term for a group of chronic enteropathies characterized by persistent or recurrent gastrointestinal (GI) signs and inflammation of the GI tract. The specific steps that lead to IBD and the basis for phenotypic variation and unpredictable responses to treatment are not known. This article examines IBD in dogs, focusing on the interaction between genetic susceptibility and the enteric microenvironment (bacteria, diet), the utility of recently developed histologic criteria, the prognostic indicators, and the standardized approaches to treatment.

The prevalence and diagnostic value of perinuclear antineutrophil cytoplasmic antibodies and anti-Saccharomyces cerevisiae antibodies in patients with inflammatory bowel disease in mainland China

BACKGROUND

Perinuclear anti-neutrophil cytoplasmic (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) have been studied extensively in Western countries. We determined the prevalence of pANCA and ASCA in the mainland Chinese population and the ability of pANCA and ASCA to discriminate between ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Two hundred-six unrelated patients with IBD (UC, n=152; CD, n=54), 60 patients with other gastrointestinal diseases, and 80 healthy controls were included. Sera pANCA and ASCA titers were determined by a standardized indirect immunofluorescence technique.

RESULTS

The sensitivity, specificity, positive and negative predictive values, and positive likelihood ratio of pANCA were calculated for differentiating UC from healthy controls (43.4%, 96.3%, 95.7%, 47.2%, and 11.7, respectively) and ASCA for differentiating CD from healthy controls and (46.3%, 96.3%, 89.3%, 72.6%, and 12.5, respectively). The combination of pANCA and ASCA did not result in greater diagnostic efficiency than either test alone. pANCA was more frequent in UC with extensive or severe phenotype than others. ASCA was associated with severe CD disease activity.

CONCLUSIONS

pANCA and ASCA are useful in confirming the diagnosis of IBD and differentiating between UC and CD in an IBD cohort in central China.

Shortcomings of the inflammatory bowel disease Serology 7 panel

OBJECTIVE

The goal was to compare the predictive values of the Prometheus Inflammatory Bowel Disease (IBD) Serology 7 (IBD7) panel (Prometheus Laboratories, San Diego, CA) with the predictive values of routine blood tests in a population of children referred for initial evaluation of suspected IBD.

METHODS

Medical records of pediatric patients referred for evaluation of IBD for whom IBD7 testing was performed at Prometheus Laboratories between January 2006 and November 2008 were reviewed. Patients underwent diagnosis by pediatric gastroenterologists on the basis of clinical, radiologic, endoscopic, and pathologic evaluations.

RESULTS

A total of 394 records were identified. We excluded 90 records on the basis of age of >21 years, previous diagnosis of IBD, or unclear diagnosis. The prevalence of IBD in this cohort was 38%. The sensitivity, specificity, positive predictive value, negative predictive value, and kappa value for the serological panel were 67%, 76%, 63%, 79%, and 42%, respectively, compared with values for a combination of 3 abnormal routine laboratory test results of 72%, 94%, 85%, 79%, and 47%. The antiflagellin antibody assay, the newest assay added to the panel, had sensitivity of 50% and specificity of 53%. Repeat serological testing failed to produce consistent results for 4 of 10 patients.

CONCLUSION

Despite its recent inclusion of the antiflagellin assay, the IBD7 panel has lower predictive values than routine laboratory tests in pediatric screening for IBD.

Ulcerative colitis practice guidelines in adults: American College Of Gastroenterology, Practice Parameters Committee

Guidelines for clinical practice are aimed to indicate preferred approaches to medical problems as established by scientifically valid research. Double-blind placebo controlled studies are preferable, but compassionate-use reports and expert review articles are used in a thorough review of the literature conducted through Medline with the National Library of Medicine. When only data that will not withstand objective scrutiny are available, a recommendation is identified as a consensus of experts. Guidelines are applicable to all physicians who address the subject regardless of specialty training or interests and are aimed to indicate the preferable but not necessarily the only acceptable approach to a specific problem. Guidelines are intended to be flexible and must be distinguished from standards of care, which are inflexible and rarely violated. Given the wide range of specifics in any health-care problem, the physician must always choose the course best suited to the individual patient and the variables in existence at the moment of decision. Guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the board of trustees. Each has been intensely reviewed and revised by the Committee, other experts in the field, physicians who will use them, and specialists in the science of decision analysis. The recommendations of each guideline are therefore considered valid at the time of composition based on the data available. New developments in medical research and practice pertinent to each guideline will be reviewed at a time established and indicated at publication to assure continued validity. The recommendations made are based on the level of evidence found. Grade A recommendations imply that there is consistent level 1 evidence (randomized controlled trials), grade B indicates that the evidence would be level 2 or 3, which are cohort studies or case-control studies. Grade C recommendations are based on level 4 studies, meaning case series or poor-quality cohort studies, and grade D recommendations are based on level 5 evidence, meaning expert opinion.

Noninvasive methods in evaluation of inflammatory bowel disease: where do we stand now? An update

The inflammatory bowel diseases, consisting of Crohn's disease, ulcerative colitis and indeterminate colitis, are distinguished by idiopathic and chronic inflammation of the digestive tract. The distinction between inflammatory bowel diseases and functional bowel disorders, such as irritable bowel syndrome, can be complex because they often present with similar symptoms. Rapid and inexpensive noninvasive tests that are sensitive, specific and simple are needed to prevent patient discomfort, delay in diagnosis, and unnecessary costs. None of the current commercially available serological biomarker tests can be used as a stand-alone diagnostic in clinics. Instead, these are used as an adjunct to endoscopy in diagnosis and prognosis of the disease. Along these lines,, fecal lactoferrin and calprotectin tests seem to be one step further from other tests with larger number of studies, higher sensitivity and specificity and wider availability.

Laboratory evaluation of inflammatory bowel disease

PURPOSE OF REVIEW

Recognizing inflammatory bowel disease (IBD) is straightforward when alarm symptoms are present, such as bloody diarrhea and weight loss. When the presentation is subtle or atypical, physicians must determine which patients warrant evaluation for IBD. Appropriate use of noninvasive tests can help identify which patients should undergo further investigation.

RECENT FINDINGS

Currently IBD serologies lack high enough sensitivity and specificity to make them useful as a screening test for distinguishing IBD from other disorders, but they may have a role in classifying subtypes of IBD. Fecal markers seem promising for helping to differentiate IBD from irritable bowl syndrome and for monitoring disease activity. Pharmacogenetically guided dosing is recommended for safe use of thiopurines but ongoing routine laboratory monitoring remains important. Thiopurine metabolite measurement can be useful but may not be needed in all cases.

SUMMARY

Primary care physicians should continue to rely on routine laboratory tests and clinical suspicion to decide which patients with abdominal pain to refer to a gastroenterologist. Serology panels are not useful for IBD screening as the results may lead to unnecessary procedures. Although fecal markers do show promise as a screening test for IBD, patient resistance to providing stool samples may limit its usefulness in disease monitoring. Thiopurine metabolite levels are best used in conjunction with clinical status and routine laboratory tests to monitor clinical response and adverse events.