Chloride is a negatively charged molecule known as an electrolyte. It works with other electrolytes, such as potassium, salt (sodium), and carbon dioxide (CO2), to help keep the proper balance of body fluids and maintain the body's acid-base balance.

The serum chloride test measures the amount of chloride in the fluid portion of the blood.

See also:

• Chloride in diet
• Chloride - urine test
• Sweat chloride test
• Urine electrolytes test

Blood is drawn from a vein or capillary. A laboratory machine spins the blood to separate the cells from the serum, and the level of chloride in the serum is measured.

Your doctor may tell you to temporarily stop taking certain drugs that can affect test results.

Drugs that may increase serum chloride measurements include:

• Acetazolamide
• Ammonium chloride
• Androgens
• Cortisone
• Estrogen
• Guanethidine
• Methyldopa
• Non-steroidal anti-inflammatory drugs (NSAIDs)

Drugs that may lower serum chloride measurements include:

• Aldosterone
• Bicarbonates
• Certain diuretics
• Triamterene

Never stop taking medication without first talking to your doctor.

Your doctor may order this test if you have signs of a disturbance in your body's fluid level or acid-base balance.

This test is usually ordered along with other blood tests such as a metabolic panel (CHEM-7 or CHEM-20).

A typical normal range is 96 - 106 milliequivalents per liter (mEq/L).

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

A greater-than-normal level of chloride is called hyperchloremia. It may be due to:

• Certain drugs, including carbonic anhydrase inhibitors (used to treat glaucoma)
• Dehydration
• Metabolic acidosis
• Respiratory alkalosis
• Renal tubular acidosis
• Too much bromide

A lower-than-normal level of chloride is called hypochloremia. It may be due to:

• Addison's disease
• Burns
• Certain kidney disorders
• Chronic compensated respiratory acidosis
• Congestive heart failure
• Excessive sweating
• Gastric suction
• Metabolic alkalosis
• Overhydration
• Syndrome of inappropriate ADH secretion
• Vomiting

This test may also be done to help rule out or diagnose:

• Multiple endocrine neoplasia (MEN) II
• Primary hyperparathyroidism

Fukagawa M, Kurokawa K, Papadakis MA. Fluid & electrolyte disorders. In: McPhee SJ, Papadakis MA, Tierney LM, Jr. Current Medical Diagnosis and Treatment 2007. New York, NY: McGraw Hill; 2007.