Interpretations

Pleural Fluid:  >250 mg/dL:  suggests cholesterol effusion.  Measurement of cholesterol in body fluids is clinically important and relevant in particular to the diagnosis of a cholesterol effusion.  Cholesterol effusions are important to differentiate from chylothorax, as their etiologies and therapeutic management strategies differ.  Pseudochylous or chyliform effusions accumulate gradually through the breakdown of cellular lipids in long-standing effusions such as rheumatoid pleuritis, tuberculosis, or myxedema, and by definition the effluent contains high concentrations of cholesterol.  The fluid may have a milky or opalescent appearance and be similar to that of a chylous effusion, which contains high concentrations of triglycerides in the form of chylomicrons.  Generally, elevated cholesterol above 250 mg/dL defines a cholesterol effusion in pleural fluid.  

Peritoneal Fluid:  >48 mg/dL:  suggests malignant ascites.  Ascites is the pathologic accumulation of excess fluid in the peritoneal cavity. Cholesterol analysis in peritoneal fluid may be a useful index to separate malignant ascites (>45-48 mg/dL) from cirrhotic ascites.  Using a cutoff value of 48 mg/dL, the sensitivity, specificity, positive and negative predictive value, and overall diagnostic accuracy for differentiating malignant from nonmalignant ascites were reported as 96.5%, 96.6%, 93.3%, 98.3%, and 96.6% respectively. (1)  1.  McPherson RA, Matthew RP, Hentry JB:  Cerebrospinal, Synovial, and Serous Body Fluids.  In Henry's Clinical Diagnosis and Management by Laboratory Methods.  Philadelphia, Saunders Elsevier, 2007, pp 426-454.