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 sample collected for testing?
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
How is it used?
A chloride blood test is used to detect abnormal concentrations of chloride. It is often ordered, along with other electrolytes, as part of a regular physical to screen for a variety of conditions.
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 (pH) balance.
Chloride and electrolyte tests may also be ordered 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, a healthcare practitioner will look for and address the disease, condition, or medication causing the imbalance and may order electrolyte testing at regular intervals to monitor the effectiveness of treatment. If an acid-base imbalance is suspected, the healthcare practitioner may also order tests for blood gases to further evaluate the severity and cause of the imbalance.
In persons with too much base, urine chloride measurements can tell the healthcare practitioner whether the cause 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.
When is it ordered?
The blood chloride test is almost never ordered by itself. It is usually ordered as part of an electrolyte panel, a basic metabolic panel, or a comprehensive metabolic panel, which are ordered frequently as part of a routine physical.
- Prolonged vomiting and/or diarrhea
- Weakness, fatigue
- Difficulty breathing (respiratory distress)
Electrolytes may be ordered at regular intervals when a person has a disease or condition or is taking a medication that can cause an electrolyte imbalance. Electrolyte panels or basic metabolic panels are commonly used to monitor treatment of certain problems, including high blood pressure (hypertension), heart failure, and liver and kidney disease.
A urine chloride test may be performed along with a blood or urine sodium when evaluating the cause of low or high blood chloride levels. A healthcare practitioner will look at whether the chloride measurement changes mirror those of the sodium. This helps the healthcare practitioner determine if there is also an acid-base imbalance and helps to guide treatment.
What does the test result mean?
An increased level of blood chloride (called hyperchloremia) usually indicates dehydration, but can also occur with other problems that cause high blood sodium, such as Cushing syndrome or kidney disease. Hyperchloremia also occurs when too much base is lost from the body (producing metabolic acidosis) or when a person hyperventilates (causing respiratory alkalosis).
A decreased level of blood chloride (called hypochloremia) occurs with any disorder that causes low blood sodium. Hypochloremia also occurs with congestive heart failure, prolonged vomiting or gastric suction, Addison disease, emphysema or other chronic lung diseases (causing respiratory acidosis), and with loss of acid from the body (called metabolic alkalosis).
An increased level of urine chloride can indicate dehydration, starvation, Addison disease, or increased salt intake. If both chloride and sodium levels are high in a person on a restricted salt diet, the person is not complying with the diet.
Is there anything else I should know?
Drugs that affect sodium blood levels will also cause changes in chloride. In addition, swallowing large amounts of baking soda or substantially more than the recommended dosage of antacids can also cause low blood chloride.
Are there dietary recommendations for chloride?
Yes. The Food and Nutrition Board at the Institute of Medicine recommends that adolescents and adults ages 14 to 50 years consume 2.3 g/day. The recommendations vary based on age, sex, and other factors. Chloride is readily available in the food supply and most Americans probably consume more than necessary, in the form of table salt and salt in prepared foods. It is also found in many vegetables and in foods such as salted meats, butter, tomatoes, lettuce, celery, and olives.
What treatment is prescribed for abnormal chloride levels?
On This Site
Tests: Sodium, Potassium, Bicarbonate, Electrolytes, Comprehensive Metabolic Panel, Basic Metabolic Panel, Blood Gases
Conditions: Acidosis and Alkalosis, Addison Disease, Cushing Syndrome, Hypertension, Congestive Heart Failure, Lung Diseases, Kidney Disease, Diarrhea
Elsewhere On The Web