Overview

• Contains albumin and globulin fractions.
• Globulin fraction = alpha, beta and gamma subfractions.
• Absolute changes in albumin and globulin associated with wide range of clinical conditions.
• Electrophoresis: separation of globulin sub-fractions provides further information.

Sampling

Tests

Methodologies

• Biuret: standard method (colorimetric).
• Calibrated refractometer: for rapid result.
• Temperature-controlled instrument recommended.
• Electrophoresis Serum protein electrophoresis : followed by scanning with densitometer to quantify individual globulin subfractions.

Availability

• Biuret: widely available.
• Refractometer: widely available.
• Electrophoresis: commercial laboratories.

Validity

Sensitivity

• Biuret: accurate except at low levels (<10 g/l).
• Refractometer: generally satisfactory for clinical purposes not sensitive enough to detect low levels of protein found in body fluids other than serum.

Specificity

• Biuret method highly specific for protein.

Technique (intrinsic) limitations

• Usually must be interpreted in conjunction with other laboratory and clinical findings to reach a diagnosis.

Technician (extrinsic) limitations

• Electrophoresis.
• Biuret: hemolysis and/or lipemia may result in increased total protein.
• Refractometer: usually slight to moderate hemolysis or icterus will not interfere with reading. Turbidity of lipemia interferes with light transmission and ability to obtain an accurate reading.

Result Data

Further Reading

Publications

Referred papers

• Recent references from VetMedResource and PubMed.

Other sources of information

• Ettinger S J, Feldman E C, Cote E (2017) Eds. Textbook of Veterinary Internal Medicine. 8th edn. Elsevier, USA.
• Stockham S L & Scott M A (2002) Fundamentals of Veterinary Clinical Pathology. Iowa State Press, USA.
• Kaneko J J, Harvey J W & Brass M L (1997) Eds. Clinical Biochemistry of Domestic Animals. 5th edn. Academic Press, USA.
• Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine. Clinical Pathology. 3rd edn. Iowa University Press, USA.