Consider alternative diagnoses at the same time
Cell count with differential
Gram stain
Culture (10cc in blood culture bottle)
Glucose
Protein
Albumin and SERUM albumin
LDH and SERUM LDH at same time
Amylase
TB smear and culture
Cytology
TG
Billirubin
Paracentesis results supporting a diagnosis of<unk> :
Absolute neutrophil count (PMNs) ≥250, pH <7.35, OR blood-ascites pH gradient >0.1<unk> on gram stain (single type)
SAAG > 1.1
Diagnostic of portal hypertension with 97% accuracy<unk>  rarely develops in patients without portal hypertension
Protein < 1, Glucose > 50 (otherwise concern for secondary<unk>  peritonitis)
Absolute neutrophil count (PMNs) ≥250, pH <7.35, OR blood-ascites pH gradient >0.1<unk> on gram stain (single type)
SAAG > 1.1
Diagnostic of portal hypertension with 97% accuracy<unk>  rarely develops in patients without portal hypertension
Protein < 1, Glucose > 50 (otherwise concern for secondary<unk>  peritonitis)
Diagnostic of portal hypertension with 97% accuracy<unk>  rarely develops in patients without portal hypertension
For bloody tap, subtract 1 WBC for every 250 RBC
See  Peritoneal dialysis-associated peritonitis
Cell count >100/mm with >50% neutrophils most consistent with infection
Importance of distinction
Mortality of secondary<unk>  peritonitis (eg. perforated appendicitis, cholecystitis) ~100% if treatment is only antibiotics without surgery
Mortality of unnecessary surgery in patients with<unk>  ~80%
Laboratory findings
Secondary<unk>  peritonitis strongly suggested by:
Neutrocytic fluid (PMN ≥250) with two or more of the following:
Total protein concentration >1 g/dL (10 g/L)
Glucose concentration <50 mg/dL (2.8 mmol/L)
LDH greater than upper limit of normal for serum
Ascitic alk phos >240
Gram stain
Large numbers of different<unk>  forms
Imaging
If evidence of secondary<unk>  peritonitis obtain abdominal imaging
If no evidence of free air or contrast extravasation then surgery is not indicated
Mortality of secondary<unk>  peritonitis (eg. perforated appendicitis, cholecystitis) ~100% if treatment is only antibiotics without surgery
Mortality of unnecessary surgery in patients with<unk>  ~80%
Secondary<unk>  peritonitis strongly suggested by:
Neutrocytic fluid (PMN ≥250) with two or more of the following:
Total protein concentration >1 g/dL (10 g/L)
Glucose concentration <50 mg/dL (2.8 mmol/L)
LDH greater than upper limit of normal for serum
Ascitic alk phos >240
Gram stain
Large numbers of different<unk>  forms
Neutrocytic fluid (PMN ≥250) with two or more of the following:
Total protein concentration >1 g/dL (10 g/L)
Glucose concentration <50 mg/dL (2.8 mmol/L)
LDH greater than upper limit of normal for serum
Ascitic alk phos >240
Gram stain
Large numbers of different<unk>  forms
Total protein concentration >1 g/dL (10 g/L)
Glucose concentration <50 mg/dL (2.8 mmol/L)
LDH greater than upper limit of normal for serum
Large numbers of different<unk>  forms
If evidence of secondary<unk>  peritonitis obtain abdominal imaging
If no evidence of free air or contrast extravasation then surgery is not indicated
If no evidence of free air or contrast extravasation then surgery is not indicated
Spontaneous bacterial peritonitis
Abdominal aortic aneurysm
Peritoneal dialysis-associated peritonitis
Aortocaval fistula
Large bowel obstruction
Acute gastroenteritis
Malignant bowel obstruction
Aortoenteric fisulta