Chlorides

Function

Chloride is one of the most important electrolytes in the blood. It helps maintain the balance of fluids inside and outside of cells, maintains proper blood volume, blood pressure, and the pH (acid-base balance) of body fluids. It is often measured alongside sodium, potassium, and bicarbonate.

Why it is Ordered

This test is part of a basic or comprehensive metabolic panel (BMP/CMP). It is used to evaluate symptoms like prolonged vomiting, diarrhea, weakness, or difficulty breathing. It is also used to monitor treatment for kidney disease or high blood pressure.

Associated Conditions

• Dehydration: Often leads to high chloride levels.
• Metabolic Acidosis/Alkalosis: Chloride levels shift to compensate for changes in blood pH.
• Kidney Disease: The kidneys are responsible for excreting or retaining chloride.
• Addison's Disease: Adrenal insufficiency can lead to low chloride levels.

Clinical Importance

Because chloride usually follows sodium (as NaCl), an isolated change in chloride without a change in sodium often points toward an acid-base disturbance. For example, in metabolic alkalosis (often caused by vomiting), the body loses chloride, leading to hypochloremia.