The cytology of the human peritoneal fluid

A series of 19 human peritoneal fluids obtained by aspiration at laparoscopy and cul-de-sac punctures were analysed for their cellular content. Four types of cells were differentiated: macrophages, mesothelial cells, lymphocytes and polymorphonuclear leukocytes. The macrophages and mesothelial cells represented the two major types of cells, each group constituiting about 36 per cent of the population, while the lymphocytes and polymorphonuclears represented 18 and 7 per cent of the population, respectively. Macrophages were identified by their capacity to engulf alcohol-killed Staphylococcus albus. It appears that by this method of macrophage identification, a more accurate representation of the cellular content of peritoneal fluid can be obtained.