• Cl

• Red (gel) top or green top tube
• 7 mL of venous blood

Chloride is the major anionic electrolyte found in the blood and extravascular spaces. Chloride is absorbed from the intestines and excreted by the kidneys.

• Chloride along with sodium maintains osmotic pressure and thus helps to regulate blood volume and arterial pressure
• Chloride is involved in the maintenance of acid-base balance
• Chloride contributes to gastric acid as hydrochloric acid for digestion and activation of enzymes

This test is performed to:

• Assist in confirming or diagnosis of disorders associated with abnormal chloride values; which often occur with acid-base or fluid imbalances
• Differentiate between types of acidosis such as hyperchloremic versus anion gap
• Monitor effectiveness (or side effects) of drug therapy that increases or decreases serum chloride levels

Additional information:

• Day to day variation is 1%
• Chloride increases just before menses
• Chloride decreases after meals
• Blind persons have lower blood Chloride levels
• Related laboratory tests include:
• Anion gap
• Blood gas analysis
• CO2
• Osmolality
• Potassium
• Sodium

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

Conditions where serum chloride levels are increased include:

• Cushing's disease
• Diabetes insipidus
• Head trauma with hypothalamic stimulation or damage
• Hyperchloremic metabolic acidosis
• IV Normal Saline
• Metabolic acidosis
• Primary hyperparathyroidism
• Renal disease
• Renal tubular acidosis
• Obstructive uropathy
• Polycystic renal disease
• Pyelonephritis
• Respiratory alkalosis
• Salicylate intoxication
• Severe dehydration

Drugs and substances that may increase serum chloride include:

• Acetazolamide
• Acetylcysteine
• Acetylsalicylic acid (Aspirin)
• Ammonium chloride
• Androgens
• Bromide
• Cannabis
• Carbamazepine
• Carvedilol
• Cefotaxime
• Chloride salts
• Cholestyramine
• Cyclosporine
• Diazoxide
• Estrogens
• Ethanol
• Guanethidine
• Iodide
• Ion exchange resins
• Lithium
• Methyldopa
• Neostigmine
• Nonsteroidal antiinflammatory drugs
• Oxyphenbutazone
• Phenylbutazone
• Thiazide diuretics
• Triamterene

Conditions where serum chloride levels are decreased include:

• G.I. Losses
• Congenital chloride-losing enteropathy
• Gastric outlet obstruction - Pyloric stenosis
• Nasogastric suction
• Secretory diarrhea
• Zollinger-Ellison syndrome
• Renal Loss
• Bartter's syndrome
• Loop diuretics
• Salt-losing nephropathies
• Others
• Addison's disease
• Burns
• Chronic respiratory acidosis
• Congestive heart failure
• Dietary deficiency
• Emphysema
• Inappropriate ADH (SIADH)
• IV hypotonic solutions
• Metabolic alkalosis
• Overhydration - Water intoxication
• Perspiration - Cystic Fibrosis

Drugs and substances that may decrease serum chloride include:

• Aldosterone
• Allopurinol
• Amiloride
• Antacids
• Ascorbic acid
• Bicarbonate
• Cefotaxime
• Chlorpropamide
• Chlorthalidone
• Corticosteroids/Hydrocortisone
• Corticotropin
• Ethacrynic acid
• Etretinate
• Hydroflumethiazide
• Laxatives (chronic abuse)
• Loop diuretics (Bumetanide, furosemide)
• Mannitol
• Meralluride
• Mersalyl
• Metolazone
• Polythiazide
• Silver
• Thiazide diuretics
• Triamterene
• Trimethoprim

• Hauhouot-Attoungbre ML et al. [Disturbances of electrolytes in severe thermal burns][Article in French]. Ann Biol Clin (Paris) 2005 Jul-Aug; 63(4): 417-21
• Hihnala S et al. Long-term clinical outcome in patients with congenital chloride diarrhea. J Pediatr Gastroenterol Nutr. 2006 Apr; 42(4): 369-75
• Khanna A et al. Metabolic alkalosis. J Nephrol. 2006 Mar-Apr; 19 Suppl 9:S86-96
• LabTestsOnline®. Chloride. [Homepage on the Internet]© 2001-2006. Last reviewed on April 15, 2005. Last accessed on October 19, 2006. Available at URL: http://www.labtestsonline.org/understanding/analytes/chloride/
• Sahu A et al. The initial anion gap is a predictor of mortality in acute myocardial infarction. Coron Artery Dis. 2006 Aug; 17(5): 409-12
• Sessler J et al. Calix[4]pyrrole as a Chloride Anion Receptor: Solvent and Countercation Effects. J Am Chem Soc. 2006 Sep 20; 128(37): 12281-12288
• Story D a et al. Hyperchloremic acidosis in the critically ill: one of the strong-ion acidoses? Anesth Analg. 2006 Jul; 103(1): 144-8, table of contents
• Pei D et al. The influence of chromium chloride-containing milk to glycemic control of patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial. Metabolism. 2006 Jul; 55(7): 923-7
• http://www.utmb.edu/lsg/labsurvivalguide/chem/chlorid3.htm