First exchange neutrophilia is not always an index of peritonitis during CAPD

To date, the medical literature suggests that CAPD patients with peritonitis have an increase in the dialysate white cell count (greater than 100 cells mL) with neutrophilia (greater than 50%). In order to explore the differential composition of the peritoneal fluid cells (P.F.C.), we have followed 21 patients (PTS) twice a month over a 30-month period. Nine hundred and fifty samples obtained either from the 24 hours (hrs) drained CAPD fluid, or from the "First Morning Exchange" (F.M.E.) during the same day, when possible, were estimated with the "Millipore Filter" (5-8 Micron (lw) pore size), stained by the Papanicolau method. The results can be so summarized: (1) 13 PTS (62%) showed constantly a low polynuclear count (3-32%); (2) 8 non-infected PTS (38%) showed constantly a higher neutrophilia (40-80%); and (3) from time to time the PTS of the two groups showed a higher neutrophilia and an increased cellularity during clinical infection. In all the samples, the differential P.F.C. count was not affected by the dialysate composition and no difference was observed between the 24 hrs samples and the F.M.E. samples made on the same day. Differential peritoneal cell count may be useful when there are important changes in the stable individual composition.