Polymorphonuclear leukocytes (PMNs), also known as neutrophils, are a type of white blood cell. The determination of the PMN count in ascitic fluid involves identifying and quantifying these cells within a sample obtained via paracentesis. A manual cell count is performed using a hemocytometer after diluting the ascitic fluid. Alternatively, automated cell counters found in many clinical laboratories can be employed for cell enumeration. A PMN count exceeding 250 cells/mm3 (0.25 x 109/L) is a significant diagnostic indicator. For instance, an ascitic fluid sample diluted 1:10 with a cell count of 300 cells/mm3 on the hemocytometer corresponds to an actual count of 3000 cells/mm3, requiring further analysis to determine the PMN percentage.
Assessing the concentration of these specific leukocytes in ascitic fluid is a critical diagnostic step in evaluating patients with ascites. An elevated count is often indicative of spontaneous bacterial peritonitis (SBP), a serious infection in individuals with cirrhosis. Accurate quantification aids in prompt diagnosis and initiation of appropriate antibiotic therapy, thereby improving patient outcomes and reducing the risk of complications. Historically, microscopic examination and manual cell counting were the standard methods. The development of automated cell counters has enhanced the speed and precision of this diagnostic procedure.
