What is Chloride - Body fluid

Also Known As: Cl

Formal Name: Chloride, serum, Chloride, urine random, Chloride urine 24 hour

Chloride is an electrolyte. It is a negatively charged ion that works with other electrolytes, such as potassium, sodium, and bicarbonate, to help regulate the amount of fluid in the body and maintain the acid-base balance. This test measures the level of chloride in the blood and/or urine.

Chloride is present in all body fluids but is found in the highest concentration in the blood and in the fluid outside of the body’s cells. Most of the time, chloride concentrations mirror those of sodium, increasing and decreasing for the same reasons and in direct relationship to sodium. When there is an acid-base imbalance, however, blood chloride levels can change independently of sodium levels as chloride acts as a buffer. It helps to maintain electrical neutrality at the cellular level by moving into or out of the cells as needed.

We get chloride in our diet through food and table salt, which is made up of sodium and chloride ions. Most of the chloride is absorbed by the digestive tract, and the excess is eliminated in urine. The normal blood level remains steady, with a slight drop after meals (because the stomach produces acid after eating, using chloride from blood).

How is the test used?

A chloride blood test is used to detect an abnormal level of chloride. It is often used, along with other electrolytes tests, as part of a routine health exam to screen for a variety of conditions.

Chloride and other electrolyte tests may also be used to help diagnose the cause of signs and symptoms such as prolonged vomiting, diarrhea, weakness, and difficulty breathing (respiratory distress). If an electrolyte imbalance is detected, your healthcare practitioner will look for and address the disease, condition, or medication causing the imbalance and may use a series of electrolyte tests to monitor the effectiveness of treatment. If an acid-base imbalance is suspected, your healthcare practitioner may also order tests for blood gases to further evaluate the severity and cause of the imbalance.

Urine chloride tests may be used by your healthcare practitioner to determine whether the cause of alkalosis (too much base) is loss of salt (in cases of dehydration, vomiting, or use of diuretics, where urine chloride would be very low) or an excess of certain hormones such as cortisol or aldosterone that can affect electrolyte elimination.