Unifying Concepts

Diagnosis of Spontaneous Bacterial Peritonitis (SBP)

Spontaneous bacterial peritonitis (SBP) is a frequent complication in cirrhotic patients with ascites. Diagnosis of SBP is established by a polymorphonuclear cell count in ascitic fluid > or =250 cells/mm(3).

Indications for diagnostic paracentesis.

  • Cirrhotic patients with ascites at admission
  • Cirrhotic patients with ascites and signs or symptoms of infection: fever, leukocytosis, abdominal pain
  • Cirrhotic patients with ascites who present with a clinical condition that is deteriorating during hospitalization: renal function impairment, hepatic encephalopathy, gastrointestinal bleeding
  • Patients with new-onset ascites

Analysis of Peritoneal Fluid

Test and Ascitic-Fluid Container Comments
Albumin Differential diagnosis of ascites according to the serum–ascites albumin gradient
Cell Cell count and differential count
Culture Aerobic- and anaerobic-culture


Additional Analyses of Ascitic Fluid

Test and Ascitic-Fluid Container Comments
Tube without additives
Total protein Values >1 g/dl suggest secondary peritonitis instead of SBP
Lactate dehydrogenase Values greater than the upper limit of normal for serum suggest secondary peritonitis instead of SBP
Glucose Values <50 mg/dl suggest secondary peritonitis instead of SBP
Carcinoembryonic antigen Values >5 ng/ml suggest hollow viscus perforation
Alkaline phosphatase Values >240 U/liter suggest hollow viscus perforation
Amylase Values markedly elevated (often >2000 U/liter or five times serum levels) in patients with pancreatic ascites or hollow viscus perforation
Triglyceride Values >200 mg/dl suggest chylous ascites
Syringe or evacuated container
Cytology Sensitivity increased if three samples submitted and promptly evaluated
Mycobacterial culture Sensitivity only 50%


Differential Diagnosis of Ascites According to the Serum–Ascites Albumin Gradient

Gradient >1.1 g/dl (portal hypertension) Gradient <1.1 g/dl


Alcoholic hepatitis

Cardiac ascites

Portal-vein thrombosis

Budd-Chiari syndrome

Liver metastases

Peritoneal carcinomatosis

Tuberculous peritonitis

Pancreatic ascites

Biliary ascites

Nephrotic syndrome


The diagnosis of SBP is suggested by a polymorphonuclear (PMN) cell count in excess of 250 cells per cubic millimeter in the absence of evidence of an alternative source of infection (secondary peritonitis), such as viscus perforation or intraabdominal abscess.

Determination of total protein, lactate dehydrogenase, and glucose levels in ascitic fluid may aid in the differentiation between SBP and secondary peritonitis. Culture is used to confirm the diagnosis of SBP.



  1. Fernandez J, Bauer TM, Navasa M, Rodes J. Diagnosis, treatment and prevention of spontaneous bacterial peritonitis. Baillieres Best Pract Res Clin Gastroenterol. 2000 Dec;14(6):975-990. [Medline]
  2. Thomsen TW, Shaffer RW, White B, Setnik GS. Videos in clinical medicine. Paracentesis. N Engl J Med. 2006 Nov 9;355(19):e21. [Medline]
Created: Apr 17, 2007
  • Language:

  • Users Online

  • Medical Disclaimer

    El contenido de este sitio web son solo para fines informativos y no reemplazan la consulta con un profesional médico.
  • Recent Posts

  • Categories

  • Copyright by