Background-Faecal concentrations of the protein calprotectin have been found to be elevated in patients with colorectal neoplasia, suggesting that it might be used as a screening tool for colorectal cancer as well as adenomas. Aims-To measure the sensitivity and specificity of faecal calprotectin for the detection of adenomas in high risk individuals undergoing colonoscopy. Also, to investigate between and within stool variability of calprotectin concentrations. Subjects-A total of 814 patients planned for colonoscopy were included for the following indications: positive faecal occult blood test, 25; neoplasia surveillance, 605; newly detected polyp, 130; and family risk, 54. Methods-Two faecal samples from each of two stools were analysed using the PhiCal ELISA test device (Nycomed Pharma AS). Results-Adenoma patients had significantly higher calprotectin levels than normal subjects (median 9.1 (95% confidence interval 7.5-10.1) v 6.6 (5.6-7.4)mg/l). There was no significant decrease in calprotectin levels after polypectomy. Levels in cancer patients were significantly higher than those in all other subgroups (median 17.6 mg/l (11.5-31.0)). With a cut oV limit of 10 mg/l, the sensitivity for cancer was 74% and for adenoma 43%. Corresponding specificity values were 64% for no cancer and 67% for no neoplasia (cancer+adenoma). Specificity varied from 71% for one stool sample to 63% for four samples. Stool variability was small, suggesting that two spots from one stool were as discriminative as two spots from each of two stools. Conclusions-The sensitivity and specificity of faecal calprotectin levels as a marker for colorectal adenoma and carcinoma justifies its use in high risk groups, but specificity is too low for screening of average risk persons. Lack of a decrease in levels after polypectomy may be due to a more widespread leucocyte migration into the intestinal lumen than that at the polyp site, and needs further investigation. (Gut 2000;46:795-800)

The majority of patients with colorectal cancer have increased fecal concentration of calprotectin. One single fecal spot seems to be sufficient for determination of the calprotectin level. Measurement of fecal calprotectin may possibly become of value as a marker for colorectal cancer, although calprotectin, similar to fecal occult blood (FOB) tests, is a non-specific test for colorectal pathology, also being elevated in inflammatory bowel diseases. Further investigation of its specificity is therefore needed.

Fecal calprotectin (CPT) is elevated in the majority of patients with known colorectal cancer (CRC), but the specificity is not clarified. Aim: To evaluate if a CPT test (PhiCal ELISA) was more sensitive than Hemoccult II test in detecting colorectal neoplasia, and to obtain reference values in subjects with normal colonoscopy. To evaluate a possible relation between number and extent of dysplasia of adenomas in first degree relatives of patients with CRC and the stage of the carcinoma in the index casus. Further to study the prevalence of CRC and adenomas in the first degree relatives of patients operated for CRC. Method: In a multicenter study, 253 first degree relatives of patients with CRC, aged 50–75 years (mean age 60 years) underwent colonoscopy after having delivered stool samples and three Hemoccult II slides. Results: In 237 first degree relatives from 148 patients with CRC, polyps were found in 118 (50%). Seventy three (31%) had adenomas and 17 had adenomas ≧10 mm. Five had asymptomatic cancers. The specificity of fecal CPT for adenomas at cut off levels ≤10, ≤15 and ≤20 mg/l were 47.4, 59.6 and 71.1%, respectively (max of three samples). The sensitivity at same cut off levels was 56.2, 45.2 and 31.5% and 4/5 of patients with carcinoma had CPT values >15 mg/l. The sensitivity of Hemoccult II for adenomas was 8%, and 4/5 of patients with carcinoma had negative Hemoccult II. The specificity for adenomas was 95%. Conclusion: Fecal CPT test was more sensitive than Hemoccult II in detecting colorectal neoplasia but the specificity was lower. In a high risk group like first degree relatives of patients with CRC, there are good reasons to consider fecal CPT as a first test in selecting patients for endoscopy.

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