Serum Chloride Blood Test

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A serum chloride blood test is done to measure how much chloride is in the serum part of blood. Chloride is an electrolyte. It works with sodium, potassium, carbon dioxide, and other electrolytes to maintain proper body fluid balance and the body’s acid-base balance.

Why this Test is Performed

If a patient’s acid-base balance or fluid level is disturbed, their doctor may order this test. This test may also be ordered along with other diagnostic blood tests like a metabolic panel test.

Preparation and Procedure

Certain drugs may have to be stopped temporarily to ensure accurate test results. The patient’s doctor will let them know which drugs to stop and no patient should stop a drug without doctor’s consent. Drugs that will possibly increase serum chloride measurements are:

  • Ammonium chloride
  • Cortisone
  • Guanethidine
  • Non-steroidal anti-inflammatory drugs
  • Acetazolamide
  • Androgens
  • Estrogens
  • Methyldopa

Drugs that will possibly lower serum chloride measurements are:

  • Bicarbonates
  • Triamterene
  • Aldosterone
  • Certain diuretics

This test requires a blood sample. Older children and adults will have their blood drawn with a needle. A health care provider will insert a needle into one of the patient’s veins and then their blood will collect into an airtight vial. A lancet will be used on infants, and often for younger children, to draw some blood and a sample of this blood will then be taken.


96 to 106 milliequivalents per liter is a typical normal range. If chloride levels are higher than normal, it is referred to as hyperchloremia. This may be caused by:

  • Dehydration
  • Respiratory alkalosis
  • Too much bromide
  • Certain drugs, such as carbonic anhydrase inhibitors
  • Metabolic acidosis
  • Renal tubular acidosis

If chloride levels are lower than normal, it is referred to as hypochloremia. This may be caused by:

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

A serum chloride test may also be performed to help diagnose or rule out:

  • Primary hyperparathyroidism
  • Multiple endocrine neoplasia II

Possible Risks

This blood test is very routine and involves simply inserting a needle into a vein to draw out a blood sample. This makes this test relatively safe and the risk involved is very slim. Some patients may be harder to get blood from. If a patient knows that they typically have difficulty giving blood, they should let their health care provider know before having this test. The risks are slight, but may include:

  • Feeling lightheaded
  • Infection
  • Excessive bleeding
  • Hematoma

To reduce hematoma, some patients may be asked to temporarily stop taking any drugs that may thin the blood, or adjust the dose.


MedlinePlus. (2009). Chloride Test – Blood. Retrieved on November 21, 2010 from MedlinePlus:

Lab Tests Online. (2010). Chloride. Retrieved on November 21, 2010 from Lab Tests Online: