Overview

• 98% of potassium is intracellular but passive and freely diffusable in and out of cells.
• Distribution across cell membrane crucial in cardiac and neuromuscular membrane potentials.
• Major intracellular cation.
• Intracellular location maintained by ATP - dependent sodium:potassium pump.
• Changes in plasma levels reflect fluid balance, rate of renal excretion and changes in balance between intra- and extracellular fluid.

Sampling

Tests

Methodologies

• Ion-specific electrode most commonly used.

Availability

• Widely available at commercial laboratories.

Technique (intrinsic) limitations

• Test results only significant in conjunction with other laboratory results and clinical findings.

Result Data

Further Reading

Publications

Refereed papers

• Recent references from VetMedResource and PubMed.

Other sources of information

• Ettinger S J & Feldman E C (2000) Eds. Textbook of Veterinary Internal Medicine. 5th edn. W B Saunders & Co, 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.