{"id":13666,"date":"2021-01-26T18:01:37","date_gmt":"2021-01-26T18:01:37","guid":{"rendered":"https:\/\/clinlabint.com\/?p=13666"},"modified":"2021-01-28T22:29:55","modified_gmt":"2021-01-28T22:29:55","slug":"value-of-calprotectin-analysis","status":"publish","type":"post","link":"https:\/\/clinlabint.com\/value-of-calprotectin-analysis\/","title":{"rendered":"Value of calprotectin analysis"},"content":{"rendered":"
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Value of calprotectin analysis<\/h1>\/ in Featured Articles<\/a> <\/span><\/span><\/header>\n<\/div><\/section>
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by Dr Ruth Ayling<\/em><\/p>\n

Calprotectin is a protein derived from neutrophils and its presence in feces can be used as a surrogate marker of gastrointestinal inflammation. Measurement is useful to differentiate inflammatory bowel disorder (IBD) from functional bowel disease, which has similar clinical features but different etiology, and to manage patients with established IBD.<\/strong><\/p>\n

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Calprotectin and its use in gastrointestinal disease<\/h3>\n

Calprotectin is a 36-kDa member of the S100 family of calcium binding proteins. It is a heterodimer of the proteins S100A8 and S100A9 each of which can bind two Ca2+ ions and other divalent metal ions, for example zinc (Fig. 1). Calprotectin has a direct antimicrobial effect related to its ability to chelate metal ions and is involved in the innate immune response. Calprotectin is derived predominantly from neutrophils and accounts for about 60% of their cytosolic protein. It is found in various body fluids in proportion to the severity of any existing inflammation. The concentration of calprotectin in the feces of healthy individuals is about six times that of normal plasma, which led to the concept of its measurement in feces as a marker of gastrointestinal inflammation.<\/p>\n

Gastrointestinal disorders are common and make up a sizeable proportion of the workload in primary care. Symptoms may be the result of disorders which have a demonstrable pathology or arise from functional disorders, in which gastrointestinal symptoms occur but no cause for them can be found. The inflammatory bowel disorders (IBDs) ulcerative colitis (UC) and Crohn\u2019s disease (CD) are two organic bowel diseases for which calprotectin measurement has particular relevance. IBDs are believed to occur in a genetically susceptible host as a result of dysregulation of the immune response to commensal microbiota, but their pathophysiology is not completely determined. Both disorders are most common in young patients, peak incidence occurring between 15 and 30 years of age, with a peak prevalence of up to 0.5% in Western countries. CD can affect any part of the gastrointestinal tract and the characteristic histological appearance is of granulomatous inflammation which is transmural in extent. In UC, disease activity is limited to the colon and the inflammation is confirmed to the mucosal layer. The most common functional bowel disorder is irritable bowel syndrome, which has been estimated to have a worldwide prevalence of 11.2%.<\/p>\n<\/div><\/section>
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It may not be possible to differentiate organic disorders, especially IBD from functional disorders such as irritable bowel syndrome, on the basis of clinical features alone and investigations are often required. Blood tests for the assessment of inflammation (for example C-reactive protein, erythrocyte sedimentation rate) lack the sensitivity and specificity required for diagnosis of IBD and the gold standard investigation for the diagnosis of diseases of the lower gastrointestinal tract is colonoscopy. This enables direct visualization and gives an opportunity for biopsy so that a histological diagnosis can be made. However, it requires significant healthcare resource, is unpleasant for the patient and is associated with morbidity and mortality.<\/p>\n

Use of fecal calprotectin as a simple, non-invasive marker of gastrointestinal inflammation, therefore, has great potential. Calprotectin has been shown to be highly reliable in the diagnosis of IBD, showing pooled sensitivities and specificities of 80\u201395% and 76\u201397%, respectively. In 2010 it was calculated that screening for IBD by measuring fecal calprotectin could result in a 67% reduction in the number of adults requiring colonoscopy. In 2015 use of the test in the differential diagnosis of IBD or irritable bowel syndrome was supported by the National Institute for Health and Care Excellence (NICE).<\/p>\n

IBDs tend to have a relapsing and remitting course and symptoms of gastrointestinal inflammation may be non-specific, which can complicate clinical assessment. In patients with established IBD, measurement of fecal calprotectin can be useful in ongoing disease management and may reduce the need for repeat colonoscopy. Situations in which fecal calprotectin analysis has been shown to have a clinical role include monitoring IBD activity, reduction of relapse, indicating recurrence after surgery and monitoring response to treatment, thereby facilitating timely escalation or discontinuation of treatment.<\/p>\n

Some studies have investigated the performance of calprotectin as a screening test for all organic bowel disease, including colorectal cancer. Sensitivities and specificities are less than for diagnosis of IBD alone and recent work suggests that the fecal immunochemical test (FIT) may be a superior predictor of the absence of significant bowel disease in adults in primary care.<\/p>\n

Laboratory considerations<\/h3>\n

Various issues need to be taken into consideration when measuring calprotectin and interpreting results (Box 1).<\/p>\n

Box 1. Important factors to be considered when analysing and interpreting fecal calprotectin<\/strong><\/p>\n