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Lab Test: Chloride (Serum) Level

    Lab Test
    • Chloride (Serum)
    • Measurement of serum chloride concentrations for the assessment of certain disorders manifesting with electrolyte abnormalities. 
    • This test is performed as part of multiphasic testing for what is usually called "electrolytes." 
    • By itself, this test does not provide much information, but with interpretation of the other electrolytes, chloride can given an indication of acid-base balance and hydration status.
    Reference Range
    • Neonates, Cord Blood:  96-104 mEq/L (96-104 mmol/L)
    • Neonates, 0 to 30 days:  98-113 mEq/L (98-113 mmol/L)
    • Children, older than 30 days:  98-107 mEq/L (98-107 mmol/L) *(PDR)
    • Adult/elderly:  98-106 mEq/L or 98-106 mmol/L
    • Child:  90-110 mEq/L
    • Newborn:  96-106 mEq/L
    • Premature infant:  95-110 mEq/L
    • Critical Values:  < 80 or > 115 mEq/L
    Indications & Uses
    • Hypokalemia - high serum chloride levels with hypokalemia are usually associated with low serum bicarbonate levels and may reflect either metabolic acidosis (e.g., diarrhea renal tubular acidosis) or respiratory alkalosis (e.g., cirrhosis, sepsis salicylate poisoning).
      • Low serum chloride levels with hypokalemia are usually associated with increased serum bicarbonate and metabolic alkalosis, suggesting diuretic use, vomiting, hyperaldosteronism, or abuse of licorice or laxatives as the etiology of hypokalemia. 
    • Initial evaluation and monitoring of diabetic ketoacidosis  (DKA)- chloride measurement is used to calculate plasma anion gap.  Hyperchloremic normal anion gap metabolic acidosis is present on admission in about 10% of patients with DKA and is present in nearly al patients after resolution of Ketonemia.  During treatment, severity of hyperchloremia can be exacerbated by excessive administration of 0.9% sodium chloride for hydration.
    • Metabolic acidosis - an elevated serum chloride level occurs in Hyperchloremic acidosis, a metabolic acidosis in which the anion gap is normal.  Hyperchloremia secondary to dehydration or a chronic respiratory alkalosis must be distinguished from hyperchloremic acidosis.  Evaluation of the patient's history and arterial blood gases will distinguish normal anion gap metabolic acidosis from respiratory alkalosis. 
    • Suspected acid-base balance disorder - in critically ill patients, changes in chloride concentration appear to have the greatest impact upon base excess and therefore, the overall metabolic acid-base state.  In normal anion gap metabolic acidosis, an elevated serum chloride level occurs when the serum sodium level is normal.  In metabolic alkalosis, the serum electrolyte pattern is characterized by an elevated total CO2 content, hypochloremia and hypokalemia.
    • Suspected pyloric stenosis - in infants with recurrent vomiting, a serum chloride concentration less than or equal to 98 mmol/L may be predictive of pyloric stenosis; however, give the test's low sensitivity, a higher serum chloride level would not be helpful in ruling out pyloric stenosis.  Persistent vomiting leads to hypochloremia, with a serum chloride concentration in the range of 60 to 75 mEq/L: this implies a longer duration of illness with the consequent clinical changes.  Plasma chloride level may be a reliable and valid parameter for assessing and correcting hypochloremic alkalemia during fluid resuscitation, using a target level of 106 mmol/L.
    Clinical Application

    Chloride is the major extracellular anion.  Its primary purpose is to maintain electrical neutrality, mostly as a salt with sodium.  It follows sodium (cation) losses and accompanies sodium excesses in an attempt to maintain electrical neutrality.  Chloride also affects water balance.  Finally, chloride also serves as a buffer to assist in acid-base balance. 

    Hypochloremia and hyperchloremia rarely occur alone and usually are part of parallel shifts in sodium or bicarbonate levels. 

    Changes in chloride concentration typically reflect changes in sodium concentration. When this is not the case, an acid-base disorder is usually present. 

    Increased levels may indicate:

    • Dehydration, excessive infusion of normal saline solution, metabolic acidosis, renal tubular acidosis, Cushing syndrome, kidney dysfunction, hyperparathyroidism, eclampsia, or respiratory alkalosis. 

    Decreased levels may indicate:

    • Overhydration, syndrome of inappropriate secretion of antidiuretic hormone (SIADH), congestive heart failure, vomiting or prolonged gastric suction, chronic diarrhea or high-output GI fistula, chronic respiratory acidosis, metabolic alkalosis, salt-losing nephritis, Addison disease, diuretic therapy, hypokalemia, aldosteronism, or burns. 

    Results increased in:  hypertriglyceridemia (colorimetric assay). 

    Results decreased in:  acute intermittent porphyria or postprandial state.

    Related Tests
    • Sodium, potassium, and bicarbonate - these are other electrolytes commonly measured with chloride. 
    • Chloride, urine. 
    • Basic metabolic panel
    • Comprehensive metabolic panel
    • Diabetic management panel
    • Electrolyte panel
    • Enteral/parenteral nutritional management panel
    • General health panel
    • Hypertension panel
    • Renal panel
    Drug-Lab Interactions
    • Excessive infusions of saline solution can result in increased chloride levels.
    • Drugs that ay cause increased serum chloride levels include:  acetazolamide, ammonium chloride, androgens, chlorothiazide cortisone preparations, estrogens, guanethidine, hydrochlorothiazide, methyldopa, and nonsteroidal anti-inflammatory drugs. 
    • Drugs that may cause decreased levels include:  aldosterone, bicarbonates, corticosteroids, cortisone, hydrocortisone, loop diuretics, thiazide diuretics, and triamterene.
    Test Tube Needed
    • Red or green top tube
    • Collect a venous blood sample.
    • Avoid hemolysis. 
    • Apply pressure or a pressure dressing to the venipuncture site and assess the site for bleeding.
    What To Tell Patient Before & After
    • Explain the procedure to the patient.
    • Tell the patient that some laboratories may require fasting.
    • LaGow B et al., eds. PDR Lab Advisor. A Comprehensive Point-of-Care Guide for Over 600 Lab Tests.  First ed. Montvale, NJ: Thomson PDR; 2007.
    • Pagana K, Pagana TJ eds. Mosby's Manual of Diagnostic and Laboratory Tests. 5th Ed.  St. Louis

MESH Terms & Keywords

  • Chloride