A new fecal calprotectin test for colorectal neoplasia - Clinical results and comparison with previous method

Background: Fecal calprotectin is elevated in patients with colorectal canc er (CRC). An improved method has been developed. The aim was to evaluate se nsitivity and specificity for CRC with the new fecal calprotectin method an d to compare the results with those of the original method. Methods: The st udy comprised 453 subjects including symptomatic CRC patients and CRC high risk subjects with and without CRC. Complete colonoscopy was performed. Cal protectin was measured with an enzyme linked immunosorbent assay (ELISA) us ing small (50-100 mg) feces samples. Results: Fecal calprotectin levels wer e significantly elevated in symptomatic CRC and in asymptomatic CRC detecte d in highrisk subjects. Calprotectin levels were significantly decreased 3 months after cancer removal. A cut-off limit of 50 mug/g resulted in a sens itivity of 89% in CRC patients and 79% in high risk subjects, compared to 8 9% and 75%, respectively, with the original method, using 10 mg/l as cut-of f Limit. Specificity was improved with the new method to 68% and 91% at cut -off of 50 and 150 mug/g, compared to 66% and 88%, respectively. Negative p redictive value (NPV) was 99% for cut-off of 50 mug/g in the high risk popu lation. One stool sample was sufficient, but measurement of two spots in tw o stools increased sensitivity to 98% for symptomatic and 82% for asymptoma tic CRC. Conclusion: The new simple method, using small samples of feces, h ad a higher diagnostic accuracy, suggesting that it should be preferred to the original one, in screening high risk groups for CRC.