Differentiation of exudate from transudate ascites based on the dipstick values of protein, glucose, and pH

The aim of present study was to determine the reliability of the dipstick values (protein, glucose, and pH) for differentiation of exudate from transudate ascites in comparison with the serum-ascites albumin gradient as criterion standard. A total of 100 patients with ascites (58 males and 42 females; mean age, 55.6 ± 16.1 years) were studied for the different causes of ascites. Peripheral blood samples were obtained, and at the same time, the patients underwent paracentesis. There were 62 cases (62.0%) of transudate ascites and 38 (38.0%) of exudates ascites, based on serum-ascites albumin gradient. Using logistic regression, we found a dipstick equation (K = 0.012Protein - 0.012Glucose - 3.329pH + 23.498) to differentiate transudate (K < 0) from exudate (K > 0) ascites. The sensitivity, specificity, positive predictive value, and negative predictive value of dipstick equation to diagnose ascites as transudate and exudate were 93.8%, 94.4%, 96.8%, and 89.5%, respectively, and 94.4%, 93.9%, 89.5%, and 96.9%, respectively. The area under the receiver operating characteristic curve was 0.915 (95% confidence interval, 0.848-0.982; P < .001). We concluded that the dipstick can be an inexpensive, rapid, and simple option for categorizing ascites into transudate and exudate and can be used routinely for this purpose in clinical practice.