Rapid Diagnosis of Spontaneous Bacterial Peritonitis by Use of Reagent Strips

Abstract

We studied the use of reagent strips for diagnosis of spontaneous bacterial peritonitis (SBP) in cirrhotic patients with ascites. A reagent strip for leukocyte esterase designed for the testing of urine with a colorimetric 5-grade scale (0 to 4) was used to evaluate ascitic fluid in 228 nonselected paracentesis performed in 128 cirrhotic patients. We diagnosed 52 SBP and 5 secondary bacterial peritonitis by means of polymorphonuclear cell count and classical criteria. When we considered positive a reagent strip result of 3 or 4, sensitivity was 89% (51 of 57), specificity was 99% (170 of 171), and positive predictive value was 98%. When we considered positive a reagent strip result of 2 or more, sensitivity was 96% (55 of 57), specificity was 89% (152 of 171), and negative predictive value was 99%. In conclusion, the use of reagent strips is a rapid, easy to use, and inexpensive tool for diagnosis of ascitic fluid infection. A positive result should be an indication for empirical antibiotic therapy, and a negative result may be useful as a screening test to exclude SBP. (HEPATOLOGY 2003;37: 893-896.)See Editorial on Page 745 S pontaneous bacterial peritonitis (SBP) is a frequent and severe complication in cirrhotic patients with ascites. The prevalence of SBP in unselected patients admitted to the hospital ranges between 10% and 30%. 1 Although infection resolution is high with antibiotic therapy, in-hospital mortality is still over 20%, 2 mainly secondary to hepato-renal syndrome.Sensitive methods of ascitic fluid cultures reach 80% positivity in patients with SBP in the context of clinical trials, 3,4 but, in clinical practice, ascites culture is negative in more than 60% of patients with SBP, 5 and culture results are delayed for several days; thus, diagnosis of SBP must be based on the polymorphonuclear (PMN) cell count. In ascitic fluid, a count of more of 250/mm 3 is highly indicative of SBP and is an indication for antibiotic therapy. However, the ascitic fluid total leukocyte and PMN count is not always available everywhere or cannot be done in an emergency basis.Use of reagent strip testing for leukocyte esterase has been proposed for the rapid diagnosis of meningitis, 6 empyema, 7 urinary tract infections, 8 and peritonitis in patients on peritoneal dialysis. 9 The leukocyte esterase present in the biologic fluid reacts with a chemical compound of the reagent strip causing a color change in the azo dye (purple). The aim of this prospective study is to assess the utility of reagent strips for the rapid diagnosis of SBP in cirrhotic patients with ascites. Patients and MethodsPatients. In a university-based hospital, for an 18-month period, we studied a group of nonselected paracentesis performed on a cohort of cirrhotic patients, at admission, when an SBP was suspected or was clinically indicated. To avoid equivocal results, paracentesis performed at 48 hours after diagnosis of SBP to control infection outcome was not included in the study. Diagnosis of cirrhosis was established by histologic criteria or...

Reagent strips and spontaneous bacterial peritonitis

“…Conversely, Aution sticks (Menarini diagnostics, Firenze, Italy), showed a higher sensitivity and negative predictive value in two prospective studies. 2,3 We agree with the authors that total leucocyte and polymorphonuclear differential count in ascitic fluid remain the gold standard for SBP diagnosis; however, we must remember that the cut-off of 250 polymorphonuclear cells ⁄ lL is an arbitrarily-chosen figure to get a high sensitivity and negative predictive value, but with an accuracy far from 100%.…”

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

“…The sensitivity and specificity of the reagent strip (Aution sticks®; A. Menarini Diagnostics, Firenze, Italy) were 96% and 89%, respectively [26]. Other studies have been carried out in order to confirm the performance of different reagent strips in SBP diagnosis in inpatient and outpatient settings reaching similar results [26][27][28][29][30][31][32][33].…”

Diagnosis and management of bacterial infections in decompensated cirrhosis

“…In these cases, some guidelines recommend antibiotic treatment only if the patient shows signs of infection [8] . Leukocyte reagent strips have been suggested as a rapid screening test for the diagnosis of SBP at the bedside [23][24][25][26] . However, sensitivity varying between 45% and 100%, makes this method suboptimal for the diagnosis of SBP.…”