Fluid Proteins

Function

Fluid protein analysis is a diagnostic procedure used to determine the concentration of total protein in various body fluids, such as pleural (lung), peritoneal (abdominal), or cerebrospinal fluid (CSF). The primary function of this test is to differentiate between two types of fluid accumulation: transudates and exudates. Transudates are typically caused by systemic factors that alter hydrostatic or oncotic pressure (like heart failure), while exudates are caused by local inflammatory or neoplastic processes that increase capillary permeability.

Why it is Ordered

Physicians order this test when a patient presents with an abnormal accumulation of fluid (effusion). It is critical for narrowing down the cause of symptoms like shortness of breath (pleural effusion) or abdominal swelling (ascites). By comparing fluid protein levels to serum protein levels, clinicians apply 'Light’s Criteria' to pinpoint whether the issue is systemic or localized to the organ lining.

Associated Conditions

• Transudative causes: Congestive heart failure, Cirrhosis, Nephrotic syndrome.
• Exudative causes: Bacterial pneumonia, Malignancy (lung or breast cancer), Pulmonary embolism, Tuberculosis.
• CSF specific: Meningitis, Multiple Sclerosis, or Guillain-Barré syndrome if protein is elevated in the spinal fluid.