Normal
Adults: 96–106 mEq/L (96–106 mmol/L)
Newborns: 96–113 mEq/L (96–113 mmol/L)
Clinical Alert
Critical Values70 or >120 mEq/L (70 or >120 mmol/L
Chloride (Cl−) Level
A chloride (Cl−) level is obtained to measure the amount of chloride in the blood. Measurement of chlorides is helpful in diagnosing disorders of acid–base and water balance. Chloride, a blood electrolyte, is the major anion that exists predominantly in the extracellular spaces as part of sodium chloride or hydrochloric acid. Chloride maintains cellular integrity through its influence on osmotic pressure and acid–base and water balance. It increases or decreases in concentration in response to concentrations of other anions. In metabolic acidosis, there is a reciprocal rise in chloride concentration when the bicarbonate concentration drops. Similarly, when aldosterone directly causes an increase in the reabsorption of sodium (the positive ion), the indirect effect is an increase in the absorption of chloride (the negative ion).
Chlorides are excreted with cations (positive ions) during massive diuresis from any cause and are lost from the GI tract when vomiting, diarrhea, or intestinal fistulas occur.
In an emergency, chloride is the least important electrolyte to measure. However, it is especially important in the correction of hypokalemic alkalosis. If potassium is supplied without chloride, hypokalemic alkalosis may persist.
Obtain a 5-mL venous blood sample in a heparinized Vacutainer tube (see Chapter 2 for venous blood collection). Serum can also be used.
Observe standard precautions.
Whenever serum chloride levels are much lower than 100 mEq/L (100 mmol/L), urinary excretion of chlorides is also low.
Decreased blood chloride levels occur in the following conditions:
Severe vomiting
Gastric suction
Chronic respiratory acidosis
Burns
Metabolic alkalosis
Heart failure
Addison disease (chronic adrenal insufficiency)
Salt-losing diseases (syndrome of inappropriate antidiuretic hormone [SIADH])
Overhydration or water intoxication
Acute intermittent porphyria
Salt-losing nephritis
Increased blood chloride levels occur in the following conditions:
Dehydration
Cushing syndrome
Hyperventilation, which causes respiratory alkalosis
Metabolic acidosis with prolonged diarrhea
Hyperparathyroidism (primary)
Select kidney disorders (e.g., renal tubular acidosis)
Diabetes insipidus (DI)
Salicylate intoxication
Head injury with hypothalamic damage
Eclampsia
Pretest Patient Care
Explain test purpose and blood collection procedure.
If possible, ensure that the patient fasts at least 8–12 hours before the test.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Care
Have the patient resume normal activities and diet.
Review test results; report and record findings. Modify the nursing care plan as needed.
If an electrolyte disorder is suspected, daily weight and accurate fluid intake and output should be recorded.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
The plasma chloride concentration in infants is usually higher than that in children and adults.
Certain drugs may alter chloride levels.
Increases are associated with excessive IV saline infusions.