Measurement of calprotectin in ascitic fluid to identify elevated polymorphonuclear cell count

Figure 1 Measurement of ascitic calprotectin with the enzyme-linked immunosorbent test and the point-of-care test (Bland Altman plot). The differences between the results of the enzyme-linked immunosorbent (ELISA) and point-of-care (POC) tests in each patient are plotted against the mean of the two measurements, showing the limits of agreement, defined as the mean ± 2 SD of the difference.

Figure 2 Ascitic calprotectin values in patients with normal and elevated ascitic polymorphonuclear cell count. Box-and-whisker plot representing the median, 25^th to 75^th percentiles, minimum/maximum values, and outliers outside 1.5 times (circle) and 3 times (cross) the interquartile range of ascitic calprotectin values, measured with the enzyme-linked immunosorbent (ELISA) test (A) and the point-of-care (POC) test (B). PMN: Polymorphonuclear.

Figure 3 Receiver operating characteristics analysis of the enzyme-linked immunosorbent test and the point-of-care test to identify elevated ascitic polymorphonuclear cell count. The area under the receiver operating characteristics curve (AUC) for ascitic calprotectin for identifying a polymorphonuclear count > 250/μL. No differences between the two tests (P = 0.155) were detected. The diagonal line represents no discrimination. POC: Point-of-care; ELISA: Enzyme-linked immunosorbent.

Figure 4 Diagnostic accuracy. For the enzyme-linked immunosorbent (ELISA) test, the overall test accuracy of ascitic calprotectin was 87% when 0.63 μg/mL was used as the best cut-off value (A) and was 84% for the point-of-care (POC) test when 0.51 μg/mL was used as best cut-off (B). PMN: Polymorphonuclear.