Improved assay for fecal calprotectin

Fecal calprotectin is a marker of inflammatory and neoplastic disease in th e lower gastrointestinal tract. A new fecal sample preparation procedure fo r the measurement of calprotectin has been developed, with higher calprotec tin yield and lower contamination risk. Changes in the new method compared to the original [Roseth AG, Fagerhol MK, Aadland E, Schonsby H. Assessment of the neutrophil dominating protein calprotectin in feces. A methodologic study. Scand J Gastroenterol 1992;27(9):793-798] are smaller sample size, h igher dilution of the sample, presence of dissociating agents in the extrac tion solution and procedure performed in closed disposable tubes. The extra ction yield was 78% (41-100%) of total calprotectin, giving an overall five -fold increase compared to the original method. Samples with high calprotec tin values were increased to a slightly higher degree, than low calprotecti n samples, thus improving the separation between high and low calprotectin levels. Median calprotectin level in healthy subjects was 26 mu g/g. Pathol ogical samples with pancolitis showed levels up to 30 000 mu g/g. The mean C.V. (coefficient of variation) in blended feces was lower than that of unb lended, suggesting uneven distribution of calprotectin. However, no signifi cant difference between spot measurements was found when five samples from each of 47 stools were measured. Thus measurements of calprotectin in fecal samples were accurate and reproducible. No interference with foods or rele vant oral pharmaceuticals or nutraceuticals was found. (C) 2000 Elsevier Sc ience B.V. All rights reserved.