Miscellaneous Total Bilirubin

Body fluid specimen, including but not limited to: Cerebrospinal Fluid, pleural fluid, pericardial fluid, peritoneal fluid, or synovial fluid. Note fluid type in order comments or on patient specimen label.

Collect body fluid in a body fluid collection bag or other sterile container and transport to lab. Refrigerate if transport will be delayed. Note fluid type in order comments or on patient specimen label.  Protect specimen from prolonged exposure to light.

This test is for Total Bilirubin measurement on Body Fluids.  For Total Bilirubin measurement on plasma or serum, order TBILI.

Body fluid collection bag or sterile container

Daily upon receipt

The Body Fluid Total Bilirubin test may aid in the distinction between a transudative and an exudative body fluid, when used in conjunction with other testing including serum bilirubin analysis, body fluid; serum protein ratio, body fluids; serum lactate dehydrogenase ratio, and serum lactate dehydrogenase.

Assessing whether a body fluid specimen is exudative or transudative in nature is the initial step in determining the etiology of the fluid. Transudative fluids result from hemodynamic aberrations or oncotic changes and are associated with ultrafiltration of serum across pleural membranes. Transudates most commonly occur in association with clinically apparent conditions such as heart failure and cirrhosis. Exudative fluids tend to develop as a consequence of inflammation or malignant disorders such as tuberculosis, pneumonia, or cancer, in which capillary permeability is increased, allowing large-molecular-weight compounds to be released into the accumulating fluid. If the fluid is transudate, further diagnostic procedures are often not necessary, however the presence of an exudative fluid often triggers additional testing that may be invasive in nature.

Determination of body fluid bilirubin concentration can aid in the distinction between a transudative and an exudative fluid. Bilirubin values tend to be higher in exudates than in transudates, although there is some overlap between groups. However, a ratio of body fluids to serum bilirubin has been reported to identify exudative body fluids with sensitivity, specifically, positive predictive accuracy, and absolute accuracy equivalent to that obtained using Light's criteria for an exudative pleural fluid (pleural/serum protein ratio > 0.5, pleural/serum lactate dehydrogenase ratio >0.6, and serum lactate dehydrogenase > 200 U/L).

Elevated body fluid bilirubin is suggestive of an exudative fluid. This testing should be performed in conjunction with other testing including serum bilirubin analysis, body fluid:serum protein ratio, body fluids:serum lactate dehydrogenase ratio, and serum lactate dehydrogenase.