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

This article discusses the laboratory test to measures the amount of chloride in the fluid portion (serum) of the blood.

See also:

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

Serum chloride test

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

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 diuretic hormone ( SIADH)secretion
• Vomiting

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

• Multiple endocrine neoplasia (MEN) II
• Primary hyperparathyroidism

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

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.

Seifter JL. Acid-base disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 119.