Additional evaluation for new-onset ascites can
be guided by the history. At a minimum, a complete
blood count, comprehensive metabolic panel, and
prothrombin time should be obtained. Thrombocytopenia, hypoalbuminemia, hyperbilirubinemia, and
prolongation of the prothrombin time may indicate
portal hypertension and hepatic dysfunction. Hyponatremia develops in 28% of patients with cirrhosis
and ascites and indicates a worse prognosis.
5, 8
B-type natriuretic peptide elevated above 1000 pg/
mL can distinguish cardiac ascites from ascites due
to portal hypertension.
9 Transabdominal ultrasonog-
raphy may show liver nodularity and splenomegaly
and can also confirm the presence of ascites when
physical exam findings are equivocal. A transthoracic
echocardiogram should be obtained when there is
suspicion of heart failure. When cirrhosis is pres-
ent, echocardiography should also be performed to
screen for portopulmonary hypertension, which can
contribute to fluid retention.
New or worsening decompensation of previously
compensated cirrhosis may indicate the presence
of hepatocellular carcinoma (HCC) or portal vein
thrombosis. Abdominal imaging is required to iden-
Figure;1. Algorithm for the approach to the differential diagnosis of ascites. GI = gastrointestinal; LDH = lactate dehydrogenase;
PMN = polymorphonuclear neutrophil; RBC = red blood cell; SAAG = serum-ascites albumin gradient; SBP = spontaneous bacterial peritonitis; TP = total protein. (Reproduced with permission Runyon BA. Ascites and spontaneous bacterial peritonitis. In: Feldman
M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's gastrointestinal and liver disease. 9th ed. Philadelphia [PA]: Saunders/
Elsevier; 2010:1517–41. Copyright © 2010, Elsevier.)
Abdominal
paracentesis
Gross
appearance
of;fluid
Special;testing
or
Cell;count
correction
WBC;count
(cells/µL)
PMN;count
(cells/µL)
SAAG;(g/dL) Other;testing Working;diagnosis Confirmatory;testing
Transparent
yellow or
Crystal clear or
Cloudy yellow
Bloody
Milky
Dark brown
Subtract 1
WBC/750 RBCs
Subtract 1
PMN/250 RBCs
Triglyceride
concentration
Bilirubin
concentration
<500
≥500
<250
≥250
<50%
PMNs
≥50%
PMNs
≥
1. 1
< 1. 1
≥
1. 1
< 1. 1
≥
1. 1
< 1. 1
Single organism
in culture, TP < 1 g/dL,
Glucose >50 mg/dL,
LDH <225 U/L
< 2. 5 g/dL
Total protein
≥
2. 5 g/dL
Total protein
< 2. 5 g/dL
Polymicrobial infection,
TP > 1 g/dL,
Glucose <50 mg/dL,
LDH ≥225 U/L
Ascitic fluid amylase
>100 U/L
Send fluid for
tuberculosis testing
Positive cytology
Send fluid for
tuberculosis testing
Uncomplicated
cirrhotic ascites
Cardiac ascites
Nephrotic ascites
Secondary
bacterial peritonitis
SBP
Ultrasound and/or
liver biopsy
Chest radiograph and
echocardiogram
24-hour urine
protein excretion
Clinical response
to antibiotic
Upright abdominal
radiograph, water-soluble
contrast studies of GI tract
Abdominal
computed tomography
Search for
primary tumor
Mycobacterial
growth on culture
of laparoscopic
biopsy specimen of
peritoneum
Tuberculosis peritonitis
Peritoneal carcinomatosis
Tuberculosis peritonitis and
underlying cirrhosis
Peritoneal carcinomatosis and
portal hypertension
Pancreatic
ascites
