Differential diagnosis of ascites: biochemical basis

ABSTRACT

This study was conducted to detect and assess the value of different biochemical parameters in the serum and ascitic fluid in differential diagnosis of ascites. The study included 50 patients with ascites [26 with liver cirrhosis, 14 malignant and 10 tuberculous]. Serum and ascitic fluid determination of total proteins, albumin, cholesterol, lactic dehydrogenase [LDH], Nitric Oxide [NO], ferritin and glucose. The mean value of total serum proteins and albumin was low in cirrhotic patients than in malignant and tuberculous ones but no significant difference was found between these groups. Mean values of ascitic fluid serum proteins and albumin was low in cirrhotic patients with a highly significant difference between cirrhotic and both malignant and tuberculous [P < 0.0001], but no significant difference between malignant and tuberculous ascites was found. All cirrhotic patients had SAAG >/= 1.1 [100%] versus 3 [21.5%] of malignant and 5 [50%] of tuberculous group. No significant difference between the mean value of serum cholesterol between the three groups but the mean value of ascitic fluid cholesterol was found [26.8 +/- 5.2, 92.3 +/- 18.8 and 59.5 +/- 9.7 mg/dL] in cirrhotic, malignant and tuberculous respectively. A highly significant difference in mean value of ascitic fluid cholesteral between cirrhotics and both malignant and tuberculous groups [P < 0.0001] was present and a significant difference between malignant and tuberculous [P < 0.05] levels was also found. There was no significant difference between the mean value of serum LDH between the three groups but ascitic fluid LDH was very high in malignant group than both cirrhotic and tuberculous [58.7 +/- 12.4] versus 33.2 +/- 11 and 30.2 +/- 5.6 IU/L]. A highly significant statistical difference in the mean value of ascitic fluid LDH between malignant and each of cirrhotic and tuberculous levels [P < 0.001]. Both NO and ferritin were slightly high in ascitic fluid of cirrhotic and malignant patients but no statistical difference was found between groups either in serum or ascitic fluid. There was no statistical differences between the mean levels of serum glucose in all groups but a significant [P < 0.05] lower level was found in ascitic fluid of the tuberculous group compared with the other two groups. Conclusions: From this study we can conclude that diagnostic paracentesis is a useful procedure. The practice of ordering a battery of tests on every ascitic fluid specimen should be abandoned. Rather, an algorithm approach should be adopted in which the result of initial analysis guide us to further relevant tests that help in arriving at the etiology of ascites. From our result we can apply the following 1- Ascitic fluid albumin, ascitic fluid/serum albumin, total proteins and SAAG are the best parameters for diagnosis of sterile cirrhotic ascites. 2- Ascitic fluid cholesterol and LDH in combination in addition to high ascitic fluid proteins are useful for diagnosis of malignant ascites. 3- Ascitic fluid glucose, ascitic fluid/serum glucose ratio and high ascitic fluid total proteins were preferred for diagnosing tuberculous ascites