Evaluation of reagent strips for ascitic fluid leukocyte determination: is it a possible alternative for spontaneous bacterial peritonitis rapid diagnosis?

In order to evaluate the accuracy of a urine reagent dipstick (Multistix 10SG) to determine ascitic fluid leukocyte count, we prospectively studied 106 cirrhotic patients from April 2003 to December 2004, in two different centers (Federal University of São Paulo - UNIFESP-EPM and Federal University of Juiz de Fora - HU-UFJF) for the rapid bedside diagnosis of spontaneous bacterial peritonitis. The mean age 54 +/- 12 years, there was a predominance of males (eighty-two patients, 77%), and alcohol was the most frequent etiology (43%). Forty-four percent of patients were classified as Child B and fifty-one as Child C (51%). Abdominal paracentesis was performed both in outpatient and inpatient settings and the Multistix 10SG was tested. Eleven cases of spontaneous bacterial peritonitis were identified by means of polymorphonuclear count. If we considered the positive Multistix 10SG result of 3 or more, the sensitivity, specificity, positive and negative predictive value were respectively 71%, 99%, 91% and 98%. With a positive reagent strip result taken as grade 2 (traces) or more, sensitivity was 86% and specificity was 96% with positive and negative predictive values of 60% and 99%, respectively. Diagnostic accuracy was 95%. We concluded that the use of a urine reagent dipstick (Multistix 10SG) could be considered a quick, easy and cheap method for ascitic fluid cellularity determination in SBP diagnosis.