Faecal lysozyme: determination, reference intervals and some data in gastro-intestinal disease

After diluting faecal samples with a solution of Brij and saline and subsequently ultrafiltrating the faecal mixtures, lysozyme concentration can be reproducibly measured in the obtained faecal fluids, using a turbidimetric method. Measuring faecal lysozyme concentration enables discrimination normal individuals and patients with irritable bowel syndrome between patients with inflammatory bowel disease and colonic cancer. Lysozyme distribution in stools appears to be homogeneous. Faecal lysozyme concentration is stable when samples are stored during at least 1 wk at 6 degrees C. It appears that the lysozyme activity is directly correlated with the clinical status and severity of the disease. Faecal lysozyme may thus serve as an important tool both in diagnosis and in follow-up in the out-patients clinic for gastroenterology.