Clinical pathology updates: Pleural and peritoneal fluids - another modified transudate?

Abstract

Transudates have low cellularity (<1000/μL) and low protein (<25g/L). Causes include decreased serum osmotic pressure, early myocardial insufficiency, portal hypertension, portosystemic shunt and hepatic insufficiency. Transudates form secondary to decreased osmotic pressure if serum albumin is <15g/L unless there is concurrent hypertension (in which case albumin may be higher). It is worth noting that early uroperitoneum will often fall into this category of effusion. History and ancillary fluid analysis (potassium/creatinine) will point to uroperitoneum.