Rapid, simple, and reliable method for the diagnosis of CAPD peritonitis using the new MMP-9 test kit.

The objective of the present study was to evaluate the sensitivity and efficiency of the matrix metalloproteinase-9 (MMP-9) test kit for the diagnosis of bacterial peritonitis in patients undergoing peritoneal dialysis (PD). Peritoneal effluents were collected from seven continuous ambulatory PD (CAPD) patients with peritonitis, four patients with suspected peritonitis, 30 maintenance PD patients without infection, and seven patients at initiation of PD. The MMP-9 test kit was used to analyze 112 peritoneal effluent samples. These peritoneal effluents were also used to count leukocytes and examine microorganisms. MMP expression was measured by gelatin zymography, and activities were measured by an enzyme-linked immunosorbent assay (ELISA). The relationship between the reactivity of the test kit and the number of leukocytes in the samples was examined. There was a significant difference in the number of leukocytes in peritoneal effluents between the negative and positive groups detected by the MMP-9 test kit (P < 0.0001). The results obtained with the MMP-9 test kit were negative for peritoneal effluent samples that did not show increased cell counts. The reactivity of the MMP-9 test kit showed no significant differences among various microorganisms, and remained stable. The MMP-9 test kit appears to be a simple and reliable method for early diagnosis of CAPD peritonitis, and reflects the leukocyte count in peritoneal effluents. Copyright 2004 Wiley-Liss, Inc.