Instant diagnosis of spontaneous bacterial peritonitis using leukocyte esterase reagent strips: Nephur‐Test® vs. MultistixSG®

Abstract

Background/Aim: Spontaneous bacterial peritonitis (SBP), defined by an ascites neutrophil count >250/μl, is a severe complication of cirrhosis and demands prompt diagnosis. Leukocyte esterase reagent strips can rapidly detect leukocytes in physiological fluids. We compared the performance of two leukocyte esterase reagent strips in the diagnosis of SBP.Methods: Non‐selected patients with cirrhosis and ascites were prospectively included in a Community Hospital. Manual ascites cytology, culture and biochemistry were compared with the Nephur‐Test^® (read at 60 s: negative+1 to+3) and MultistixSG^® (read at 120 s: negative, trace, +1 to +3). Multiple investigators performed the tests with repeat readings by one nurse.Results: Two hundred and forty five ascites fluid samples were obtained in 51 patients: 44% in conditions of SBP antibiotic prophylaxis, 64% in an ambulatory setting. Seventeen samples had an ascites polymorphonuclear count of ≥250/μl, associated with a positive ascites culture in seven, obtained in 12 patients (24%), 53% in an ambulatory setting. Sensitivity, specificity, and positive and negative predictive values were: Nephur‐Test^® (88.2%, 99.6%, 93.8%, 99.1%); MultistixSG^® (64.7%, 99.6%, 91.7%, 97.4%). There was excellent agreement between the investigators and the nurse.Conclusions: Leukocyte esterase reagent strips may provide a rapid bedside diagnosis of SBP and thereby shorten time to appropriate management. The Nephur‐Test^® appeared to out‐perform MultistixSG^®. These tests might be particularly useful in ambulatory settings or whenever ascites fluid analysis is not rapidly available.