The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites.
OBJECTIVE
To compare the serum-ascites albumin gradient to the exudate-transudate concept in the classification of ascites.


METHODS
Prospective collection of ascitic fluid data from patients with well-characterized causes of ascites.


METHODS
Hepatology inpatient and outpatient ward and consult service of a large, urban hospital.


METHODS
A total of 901 paired serum and ascitic fluid samples were collected from consecutive patients with all forms of ascites.


METHODS
None.


METHODS
The utility of the serum-ascites albumin gradient and the old exudate-transudate concept (as defined by ascitic fluid total protein concentration [AFTP]) were compared for their ability in discriminating the cause for ascites formation.


RESULTS
The albumin gradient correctly differentiated causes of ascites due to portal hypertension from those that were not due to portal hypertension 96.7% of the time. The AFTP, when used as defined in the old exudate-transudate concept, classified the causes of ascites correctly only 55.6% of the time. This resulted in part because the AFTP of most spontaneously infected samples (traditionally expected to be exudates) was low, and the AFTP of most cardiac ascites samples (traditionally expected to be transudates) was high.


CONCLUSIONS
The exudate-transudate concept should be discarded in the classification of ascites. The serum-ascites albumin gradient is far more useful than the AFTP as a marker for portal hypertension, but the latter remains a useful adjunct in the differential diagnosis of ascites.
Runyon
B A
BA
University of Iowa, Iowa City.
Montano
A A
AA
Akriviadis
E A
EA
Antillon
M R
MR
Irving
M A
MA
McHutchison
J G
JG
D000418:Albumins / Q000032:analysis*; D001201:Ascites / Q000209:etiology* / Q000378:metabolism / Q000628:therapy; D001202:Ascitic Fluid / Q000737:chemistry*; D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000737:chemistry*; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis; D006801:Humans; D006975:Hypertension, Portal / Q000150:complications / Q000175:diagnosis; D010532:Peritoneal Diseases / Q000150:complications / Q000175:diagnosis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012709:Serum Albumin / Q000032:analysis*
D000418:Albumins; D012709:Serum Albumin