Diagnostic Laboratory Markers for Spontaneous Bacterial Peritonitis

Abstract

Spontaneous bacterial peritonitis (SBP) is an often-lifethreatening bacterial infection in patients with liver cirrhosis with ascites. Useful laboratory methods for early diagnosis are essential. The gold standard method for the diagnosis of SBP is a polymorphonuclear leukocyte (PMN) count of ≥250 cells/mm3 in the ascitic fluid. Some studies have investigated the usefulness of other novel laboratory methods for the diagnosis of SBP. This paper reviews studies of diagnostic markers for SBP, such as procalcitonin, calprotectin, and leukocyte esterase reagent strips in ascitic fluid. At present, serum procalcitonin is a relatively sensitive and specific marker for the diagnosis of SBP. The usefulness of ascitic levels of procalcitonin and calprotectin for differentiating between SBP and sterile ascites is still uncertain because of the small number of studies. Although the sensitivity of leukocyte esterase reagent strips for diagnosing SBP is variable, a negative test result may predict absence of SBP.