VLD 411: Veterinary Clinical Biochemistry and Laboratory Diagnosis - I (0+1)

CHLORIDE

• Chloride and bicarbonate are the principle anions (-vely charged) whereas sodium and potassium are the principle cations (+vely charged) in the plasma. Chloride ions are involved in regulation of water distribution between the tissues by maintaining osmotic pressure and normal cation and anion balance between intra and extra cellular fluids.

Method of Estimation: Modified Thiocyanate method

Principle

• In an acid medium chloride ions and mercury-II- thiocynate form thiocynate ions. These ions react with HNO3 and Iron –III –ions and effect a red colour. The intensity of the colour is directly proportional to the concentration of chloride ions .

Reagent composition

• Mercuric (II) thiocynate 2mmol/L
• Nitric acid 29mmol/L
• Ferric Nitrate 20mmol/L

Laboratory procedure

	Blank	Standard	Sample
Reagent	1000uL	1000uL	1000uL
Standard	--	10uL	--
Sample	--	--	10uL
Mix and incubate for 1 minute. Measure the absorbance of the sample and standard against reagent blank.

Calculation

• Chloride concentration. (mEq/L) = ( Absorbance of sample / Absorbance of standard ) / 100
• Chloride standard concentration = 100 mEq/Lab

Clinical Significance

• Hypochloridemia occurs with
  • Losses from the gastrointestinal tract particularly prolonged vomiting.
  • Advanced renal failure.
  • Adrenal insufficiency.
  • Exudation from burns or wounds.
  • Diabetic acidosis
• Hyperchloridemia occurs with
  • Dehydration
  • Congestive heart failure in which there is decreased renal blood flow.
  • Iatrogenically.