The concern with short dwells is that the white cell count may not cross the 100 per microliter threshold.  In cases like this the differential becomes more important.  This can become an issue with rapidly cycling APD patients.  In ampatient presenting with abdominal pain and a dry abdomen the recommendation is to infuse a liter of dialysis solution and let it dwell for a minimum of one hour. As above, the absolute WBC count may not exceed the 100/ microliter and a differential of > 50% PMNs support the diagnosis of peritonitis.