Medical Journal of The Islamic Republic of Iran (MJIRI)

  Abstract

  Background: Regarding the diagnostic errors of the classic criteria including serum ascites

  albumin gradient (SAAG), total protein concentration and the adapted Light et al’s criteria

  in distinguishing transudate versus exudates, we evaluated the ascitic fluid to serum

  bilirubin ratio as a new criteria in this regard. We also evaluated whether the combination of

  bilirubin ratio with each of these classic criteria improves the diagnostic accuracy.

  Methods: One-hundred ascitic fluid specimens were analysed prospectively whereas the

  category of fluid was assessed according to the clinical diagnosis. Sensitivity, specificity,

  positive predictive value (PPV), negative predictive value (NPV), overall accuracy, positive

  likelihood ratio (LR+), negative likelihood ratio (LR-) and the Youden’s index of each criterion

  alone and in combination with the bilirubin ratio were calculated.

  Results: SAAG seems to be the best criterion (specificity = 0.9090, PPV = 0.97, LR+ =

  8.03, Youden’s index = 0.64). Bilirubin and LDH ratio criteria had equivalent specificity

  (0.8333 and 0.8205, respectively), accuracy (0.80 and 0.81, respectively), PPV (0.54 and

  0.55, respectively), NPV (0.90 and 0.93, respectively) and LR+ (4.09 and 4.30, respectively)

  which generally were better than fluid total protein and total protein ratio but not as predictive

  as SAAG. The addition of bilirubin ratio to any criterion did not make any improvement.

  Conclusion: Ascitic fluid to serum bilirubin ratio, although not more predictive than

  SAAG, can be used as an alternative criterion in distinguishing exudative versus transudative

  ascitic fluid as it is more cost-effective in terms of laboratory processing and also more

  available.