Diagnosis requires paracentesis (needle drainage of the ascitic fluid). Ascites culture is negative in up to 60% of patients with clinical manifestations of spontaneous bacterial<unk>  (SBP), therefore, the diagnosis is based on the neutrophil count, which reaches its highest sensitivity with a cutoff  neutrophil count of > 250/mm3.
A diagnosis of<unk>  is based primarily on clinical grounds, that is on the clinical manifestations described above; if they support a strong suspicion of<unk> , 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).
Peritonitis laboratory findings
Peritonitis physical examination
Ascites laboratory findings
Ascites physical examination
Abdominal mass laboratory findings
Acute cholecystitis laboratory findings
Spontaneous bacterial peritonitis laboratory findings
Secondary peritonitis laboratory tests