Spontaneous bacterial peritonitis (SBP) is an infection of ascitic fluid that occurs without an intra-abdominal surgically treatable source (i.e., not due to perforation, abscess, etc.). It most commonly affects patients with cirrhosis and ascites and can present with fever, abdominal pain, encephalopathy, renal dysfunction, or even no symptoms.
SBP Diagnostic Criteria Calculator
SBP is diagnosed when corrected ascitic PMN ≥ 250 cells/mm³ (cells/µL), with or without positive culture. Optional RBC correction for traumatic taps.
Option A — Enter absolute PMN directly
If you enter absolute PMN here, Option B is ignored.
Option B — Calculate PMN from WBC & %PMN
Absolute PMN = WBC × (%PMN / 100).
Traumatic tap correction (optional)
Corrected PMN = absolute PMN − (RBC / 250).
Culture result (optional, for classification)
Polymicrobial growth suggests possible secondary peritonitis—evaluate urgently.
