Chloride

Background

Chloride is sometimes measured in serum and urine as part of the urea and electrolytes profile. Its concentration relative to the other major electrolytes is a useful guide to the interpretation of the state of hydration, osmolality and pH of the patient.

It is especially important to measure chloride during the correction of hypokalemic alkalosis and also during severe, prolonged vomiting, which can lower the serum chloride level. Chloride measurements are also useful in the diagnosis and treatment of cystic fibrosis.

The chloride value may be used in the calculation of the anion gap which is a useful index of electrolyte balance in the patient. At present chlorides are only done if specifically requested.

Reference ranges

Serum: 95 – 108 mmol/L
Urine: 110 – 250 mmol/24 hours

Specimen requirements

Sample type:

• Serum
• Lithium Heparin Plasma

or

• Plain urine (random or 24 hour).

Sample identification:

• Three patient identifiers from
  • Name
  • D.O.B.
  • Address
  • N.H.S. number
  • Unit Number
  should match on the specimen and request form. This check may be performed prior to centrifugation by the Central Sort department.

Turnaround time

2 hours