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Prospective evaluation of faecal neutrophil‐derived proteins in identifying intestinal inflammation: combination of parameters does not improve diagnostic accuracy of calprotectin

Background  Differentiating symptoms of irritable bowel syndrome from those of organic intestinal disease is a common clinical problem. Several neutrophil‐derived proteins have been proposed as a marker of inflammatory bowel disease.

Prospective Multicenter Study Evaluating Fecal Calprotectin in Adult Acute Bacterial Diarrhea

BACKGROUND Every year, about 2.2 million deaths occur worldwide due to diarrhea. Reliable diagnosis of patients with acute infectious diarrhea remains a formidable challenge to the clinicians. This is the first study reporting use of fecal calprotectin in diagnosing acute diarrhea. The aim was to compare the diagnostic accuracy of fecal calprotectin, fecal lactoferrin, and guaiac-based fecal occult blood test in a diverse group of consecutive patients with acute diarrhea in which routine bacterial stool cultures and cytotoxins for Clostridium difficile were performed. METHODS This was a prospective case-control multicenter study from January 2004 until October 2007 in 2383 consecutive patients with acute diarrhea. They provided stool samples for performing cultures. Patients with positive cultures and an equal number of matched controls with negative cultures underwent fecal occult blood test and calprotectin and lactoferrin assays. RESULTS Calprotectin, lactoferrin, and fecal occult blood tests demonstrated sensitivity and specificity of 83% and 87%, 78% and 54%, and 38% and 85%, respectively, for diagnosing acute bacterial diarrhea. CONCLUSIONS Calprotectin showed high correlation with bacteriologically positive infectious diarrhea compared with lactoferrin and fecal occult blood test. It may potentially revolutionize management algorithm for patients with acute diarrhea. As a screening test, calprotectin can generate results within hours to support presumptive diagnosis of infectious diarrhea, which can decide suitability of stool samples for culture.

Comparison of an established simple office-based immunological FOBT with fecal tumor pyruvate kinase type M2 (M2-PK) for colorectal cancer screening: prospective multicenter study.

OBJECTIVES:The immunological fecal occult blood test (IFOBT) has established itself as a more precise marker for colorectal cancer (CRC) screening than traditional guaiac-based FOBT. The simpler, cheaper, and more convenient newer office-based IFOBTs have been validated for diagnosing CRC. Dimeric isoenzyme of pyruvate kinase, M2-PK, expressed by tumor cells, has as well been proposed as a screening tool for CRC. This is the first study comparing fecal M2-PK as a screening biomarker for CRC against previously evaluated office-based IFOBT and colonoscopy.METHODS:Six hundred forty consecutive subjects (symptomatic, as well as for CRC screening) referred for colonoscopy for various indications across five centers in Germany provided the stool samples for performing M2-PK and an immunochemical FOB strip test. The IFOBT used was a rapid immunochromatographic assay for detection of fecal hemoglobin. For M2-PK, a commercially available sandwich enzyme-linked immunosorbent assay (ELISA) was used. The M2-PK test needs 6 h, while the office-based test can be read in just 10 min and is five times cheaper.RESULTS:Office-based IFOBT had sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios (LR) of 64.5, 96.3, 72.0, 94.9, 17.5, and 0.4 for diagnosing colorectal neoplasia (CRN), while the above performance characteristics for M2-PK at a cutoff value of 4U/mL were 72.4, 73.8, 29.0, 94.8, 2.8, and 0.8 respectively.CONCLUSIONS:This office-based IFOBT was found to have significantly higher specificity, PPV, and positive LR as compared with M2-PK. IFOBT proved to be a convenient, noncumbersome, quick, and cheap tool in patients with above-average risk for detection of CRN.