Distinguishing between malignant and cirrhotic ascites by computerized step-wise discriminant functional analysis of its biochemistry.

This study was designed to evaluate the ability of a specifically programmed computer to select those biochemical substances most capable of distinguishing "cirrhotic ascites" from "malignant ascites". After simultaneously performing selected biochemical and electrophoretic studies on fresh unstored serum and ascites of 23 patients with documented cirrhosis and 18 patients with proven malignancies, computerized step-wise discriminant analysis of the multiple input revealed that the serum-to-ascites LDH ratio was able to distinguish "cirrhotic ascites" from "malignant ascites" with greater than 86% accuracy. Assignment to proper groups was increased to 89% with the addition of the ratio to serum total protein-to-ascites total protein. The predictive value of a positive result was 100%; specificity was 100%; the predictive value of a negative result was 85%. This type of computer analysis also permits incorporation of both additional cases and new substances thus increasing predictability and reducing type II statistical errors.