Peritonitis laboratory findings

Peritonitis Main Page
Patient Information
Overview
Causes
Classification Spontaneous Bacterial Peritonitis Secondary Peritonitis
Differential Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Shivani Chaparala M.B.B.S [2]

Overview

A diagnosis of peritonitis is based primarily on clinical grounds, that is on the clinical manifestations described above; if they support a strong suspicion of peritonitis, no further investigation should delay surgery. Leukocytosis and acidosis may be present, but they are not specific findings. Plain abdominal X-rays may reveal dilated, oedematous intestines, although it is mainly useful to look for pneumoperitoneum (free air in the peritoneal cavity), which may also be visible on chest X-rays. If reasonable doubt still persists, an exploratory peritoneal lavage may be performed (e.g. in cause of trauma, in order to look for white blood cells, red blood cells, or bacteria).

Laboratory Findings

Routine laboratory studies for peritonitis include:

• CBC
• BUN, S.creatinine
• ABG analysis
• S.glucose
• Blood culture
• Serum electrolytes
• Liver Function tests
• Coagulation profile
• Urine analysis
• Amylase and Lipase levels

SBP

• Early Diagnostic paracentesis (< 72hrs) is recommended to perform in all cirrhotic patients with ascites at the time of admission and/or in case of gastrointestinal (GI) bleeding, shock, signs of inflammation, hepatic encephalopathy, worsening of liver or renal function. Paracentesis reveals an ascitic fluid with, most commonly, a total white cell count of up to 500 cells/mcL with a high polymorphonuclear (PMN) cell count (250/mcL or more) and a protein concentration of 1 g/dL (10 g/L) or less, corresponding to decreased ascitic opsonic activity.
• Ascitic fluid analysis and culture: performed before initiating antibiotic therapy by bedside inoculation of ascites ≥ 10 mL into blood culture bottles.80-90% positive and provides the highest yield.
• Recently leukocyte esterase calibrated reagent strips (LERS) to assess the PMN cell count (cut-off of > 250 PMN/mcL) are promised to provide good screening results when the strip turns any hue of tan/brown at 3 min. High degree of sensitivity, but the sensitivity is too low for routine use.