Figure 1.

Flow Cytometry Diagnostics for Peritoneal Dialysis Study Design. a) Specimens with suspected peritonitis were submitted to the clinical pathology service. Once received, pathology staff decanted aliquots for normal processing (microscopy, culture, susceptibility testing) and for flow cytometric testing. b) 104 specimens were processed as part of our “training set”-of these 88 met the ISPD guidelines for peritonitis (72 with a causative organism cultured by routine pathology, 16 culture negative). c) 30 specimens were assayed as part of our “testing set” to demonstrate performance of the assay performed prospectively: 15 culture positive peritonitis, 5 culture negative peritonitis, and 10 from patients with clinical suspicion subsequently ruled to not have peritonitis. d) Identity of organisms cultured from peritonitis cases (CONS-Coagulase-negative Staphylococci).e) 35 PD cases were selected for rapid susceptibility testing from enrichment cultures of PDE. 25 culture positive peritonitis cases (representing the most common and most challenging organisms) were tested from the isolate, with 10 specimens tested direct from PD effluent. f) Flow cytometry-assisted Antimicrobial Susceptibility Test (FAST) returns results in 3-6 hours.