Rapid diagnosis of peritonitis in peritoneal dialysis patients.

Background: Peritonitis is the major complication of peritoneal dialysis (PD) and has acute morbidity and resources implications. Episodes of peritonitis are associated with higher risk of peritoneal membrane failure. Rapid diagnosis of peritonitis would allow early antibiotic commencement with potential benefits of reduced need for in-patient care and dialysis modality change. This study examined the utility of a rapid peritonitis diagnosis method (Periscreen).

Methods: This was a prospective study in a single unit and included all PD patients presenting with symptoms or signs of peritonitis over 12 months. In each clinical circumstance in which the diagnosis or exclusion of peritonitis was required and in follow-up peritonitis cases, PD fluid was sent for standard laboratory analysis but also tested using the Periscreen strip. The relationship between this rapid diagnostic strip and standard laboratory methods for determination of PD fluid neutrophil count was determined.

Results: This study found the Periscreen strip easy to use and interpret. All 17 episodes of peritonitis (defined by ISPD criteria) were detected and results of the strip correlated closely with the laboratory cell count. In this study sensitivity of the Periscreen was 100% and specificity was 98%, positive predictive value was 95.6% and negative predictive value was 100%. Results were equally good in glucose containing fluids and icodextrin.

Conclusions: Periscreen is a sensitive, specific rapid tool for the presumptive diagnosis of peritonitis in PD patients used at the "point of care". Results correlated with the laboratory white cell count, a test that takes longer to perform. Widespread use in PD would aid in the early recognition and treatment of peritonitis.