Fecal calprotectin: assessment of a rapid test.

BACKGROUND: Calprotectin, a protein found mainly in neutrophil granulocytes, is used as an inflammatory marker, while the fecal concentration of the protein is used to detect gastrointestinal (GI) inflammation. MATERIAL AND METHODS: Fecal calprotectin in 100 stool samples was measured by the ELISA method and by a new rapid test. Eighty-two patients had fecal calprotectin measured for clinical reasons and delivered 95 stool samples. The rest were delivered by healthy volunteers. RESULTS: The association between the two tests was statistically significant (p<0.0001, chi(2) test). With calprotectin values <15 microg/g, the sensitivity and specificity of the new rapid test was 96 % (95 % confidence interval (CI), 87-100 %) and 70 % (CI, 55-83 %), respectively, with a negative predictive value of 94 % (CI, 81-99 %). With values >15 microg/g, the rapid test was less accurate, thus rendering results in this range difficult to interpret. CONCLUSIONS: The new rapid test is useful as a screening test for excluding GI inflammation when the cut-off of 15 microg/g is used. With fecal calprotectin concentrations >15 microg/g, the rapid test should be supplemented by quantitative measurement.