Canis ISSN: 2398-2942

Peritoneal fluid: protein

Overview

• Protein content varies with changes in vascular permeability and tissue injury or chemotaxis.
• Protein is elevated in inflammatory effusions, assists differentiation of transudates and exudates.

Sampling

Tests

Methodologies

• Refractometry:
  • A drop of fluid is placed on refractometer plate.
  • If fluid is opaque best to centrifuge best and measure protein of supernatant.
  • Most refractometers are calibrated to give a reading for total protein in g/dl. Multiply by 10 to convert to g/l.
  • Refractometry measures the refractive index (RI) of the fluid.
  • The RI changes proportionally to changes in protein concentration.
• Precipitation and dye binding methods.
• Urinary protein reagent strips for detection of grossly elevated total protein.
• Alternatively the protein may be measured using biochemical analyzer.

Availability

• Widely available at commercial laboratories.
• Refractometry can be done in house.

Technique (intrinsic) limitations

• Presence of a high concentration of other solutes, eg lipids, can give a false high reading by refractometry.
• Lipemic fluids often do not separate sufficiently following centrifugation.

Result Data