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This article waslast modified on 7 March 2022.
At a Glance
Why Get Tested?

To determine if there is a problem with your body’s acid-alkali (pH) balance and to monitor treatment

When To Get Tested?

If your doctor thinks that you have an electrolyte imbalance

Sample Required?

A blood sample taken from a vein in the arm or a urine sample

Test Preparation Needed?


On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Chloride is an electrolyte. When combined with sodium it is mostly found in nature as “salt.” Chloride is important in maintaining the normal acid-base balance of the body and, along with sodium, in keeping normal levels of water in the body. Chloride generally increases or decreases in direct relationship to sodium, but may change without any change in sodium when there are problems with too much acid or base in your body. Chloride is taken into the body through food. Most of the chloride is absorbed by the gastrointestinal tract, and the excess is excreted in urine. The normal blood concentration remains steady, with a slight drop after meals (because the stomach produces hydrochloric acid after eating, using chloride from blood).

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Common Questions
  • How is it used?

    Blood chloride may be useful along with sodium, to evaluate problems with the acid-base balance in the body, and to monitor treatment.

  • When is it requested?

    A blood chloride test may be requested to help evaluate kidney function and acid-base status. It may also be requested if you are in hospital and receiving intravenous (IV) fluids. If your sodium measurement is abnormal, the doctor may look at whether the chloride measurement changes in the same way. This may help the doctor to workout if there is also a problem with acid or base and may help guide treatment.

  • What does the test result mean?

    A severe elevation or loss of this electrolyte can indicate a serious fluid and electrolyte imbalance. The type of medical treatment depends on the cause of the problem.

    Increased levels of chloride (called hyperchloraemia) usually indicate dehydration, but can also occur with any other problem that causes high blood sodium. Hyperchloraemia also occurs when too much alkaline fluid is lost from the body (producing metabolic acidosis), or when a person hyperventilates (causing respiratory alkalosis).

    Decreased levels of chloride (called hypochloraemia) occur with any disorder that causes low blood sodium. Hypochloraemia also occurs with prolonged vomiting or gastric suction, chronic diarrhoea, emphysema, or other chronic lung disease (causing respiratory acidosis), and with loss of acid from the body (called metabolic alkalosis).

  • Is there anything else I should know?

    Drugs that affect sodium blood levels will also cause changes in chloride such as the use of diuretics. In addition, the chronic use of laxatives or taking more than the recommended dosage of antacids can also cause low blood chloride.

  • Where does chloride come from in the diet?

    Most chloride exists as a compound with sodium in the form of sodium chloride, or table salt.

  • What treatments are prescribed to affect chloride levels?

    The same treatments used to treat sodium imbalances - diuretics, fluid replacement, etc - may be used to treat chloride imbalance.