Canis ISSN: 2398-2942


Contributor(s): Jana Gordon, Chiara Valtolina


  • Definition: serum chloride concentration >122 mEq/L.

    Normal ranges and abnormal values are dependent on equipment used and reference ranges established for that equipment.
  • Chloride ions constitute two thirds of the anions in the plasma and other components of the extracellular fluid.
  • Chloride is the major anion filtered by glomeruli and reabsorbed in the renal tubules.
  • Chloride ions play a role in determining osmolarity and acid base status.


Predisposing factors

  • Depends on the underlying cause.


  • Change in chloride concentration caused by:
    • Any gain of chloride.
    • Change in water balance (decrease in free water). This is always associated with a proportional increase or decrease in sodium Hypernatremia Hyponatremia.
  • Chloride should be corrected for changes in sodium (changes in water balance):
    [Cl] (corrected)= [Cl](measured) x [Na] (normal) / [Na] (measured)
  • Artifactual hyperchloremia (elevated measured [Cl-], with normal corrected [Cl-]) Blood biochemistry: chloride :
    • Pure water loss:
      • Diabetes insipidus Diabetes insipidus.
      • Essential hypernatremia Hypernatremia.
      • Increased ambient temperature.
      • Primary hypodipsia.
      • Fever.
      • Inadequate access to water.
    • Hypotonic fluid loss:
      • Osmotic diuresis.
      • Gastrointestinal (vomiting, diarrhea, intestinal obstruction).
      • Renal (osmotic diuresis, chronic renal failure, acute renal failure, post-obstructive diuresis).
      • Third spacing.
      • Cutaneous losses.
  • Corrected hyperchloremia (associated with hyperchloremic [normal AG] metabolic acidosis Acid base imbalance ):
    • Pseudo hyperchloremia:
      • Lipemic sample (evaluated with colorimetric technique).
      • Therapy with potassium bromide Potassium bromide (bromide is measured as chloride in every chloride assay).
    • Excessive loss of sodium relative to chloride:
      • Diarrhea associated with gastrointestinal loss of sodium rich/chloride poor fluid.
    • Renal chloride retention:
      • Diarrhea.
      • Renal failure Kidney: chronic kidney disease (CKD) Kidney: acute kidney injury (AKI).
      • Type I renal tubular acidosis (renal tubular disorders that cause renal wasting of bicarbonate or low hydrogen ion secretion).
      • Diabetes mellitus Diabetes mellitus (in the initial or resolving phase when ketones are eliminated in urine as fast as they are generated: excretion of ketones in the urine in place of chloride).
      • Chronic respiratory alkalosis.
      • Drug induced (spironolactone Spironolactone
      • inhibits sodium reabsorption and increase chloride retention; acetazolamide Acetazolamide ).
    • Excessive gain of chloride relative to sodium:


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Biondo A W & De Morais H A (2008) Chloride a quick reference. Vet Clin Small Animal Practice 38 (3), 459-46 PubMed.
  • Schaer M (1999) Disorders of serum potassium, sodium, magnesium and chloride. J Vet Emerg Crit Care (4), 209-217 VetMedResource.
  • De Morais H A (1992) Chloride ion in small animal practice: the forgotten ion. J Vet Emerg Crit Care 2 (1), 11-24 VetMedResource.

Other sources of information

  • Small Animal Critical Care Medicine (2008) Eds D C Silverstein and K Hopper. Saunders Elsevier, St Louis, Missouri.
  • Fluid, Electrolytes and Acid-base Disorders in Small Animal Practice (2006) Eds S P DiBartola, Saunders Elsevier, St Louis Missouri.
  • The Veterinary ICU Book (2002) Eds W E Wingfield and M R Raffee. Teton New Media, Jackson Hole, WY.