Assessing lactic acid levels in body fluids such as pleural, peritoneal, synovial fluid, or cerebrospinal fluid (CSF) is a valuable test in diagnosing infectious or inflammatory conditions such as pleuritis, peritonitis, synovitis, or meningitis. Conditions with increased metabolic demand, secondary to infection or tissue damage, hypoxia show elevated lactic acid levels. Its monitoring helps in assessing the severity of inflammation and planning appropriate treatment.