Early diagnosis of peritoneal infection by simultaneous measurement of lactate concentration in peritoneal fluid and blood.

The level of lactate in peritoneal fluid has been suggested to be of great value in the early diagnosis of peritoneal infection [5]. However, this value is affected by multiple systemic factors producing lactic acidosis; these contributed to the high rate of false positive results, obtained in that study. In our study, a better correlation has been found between the peritoneal fluid to blood lactate gradient levels and the presence or absence of peritoneal infection. A threshold gradient level of 2.2 mmol/l in a total of 37 infected and 48 non-infected samples gave the best prediction with a sensitivity of 95% and a specificity of 96%.