Chloride
An electrolyte that works with sodium to maintain fluid and acid-base balance.
| Typical reference range | 98–110 mmol/L |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Chloride is the main negatively charged ion in extracellular fluid. It usually moves in parallel with sodium and also balances bicarbonate in acid-base regulation.
Why it matters
Chloride helps interpret sodium and acid-base abnormalities and is used to calculate the anion gap.
What a high result can mean
High chloride occurs with dehydration, diarrhea (loss of bicarbonate), renal tubular acidosis, excess saline infusion and some medications such as acetazolamide.
What a low result can mean
Low chloride occurs with prolonged vomiting, diuretics, heart failure, SIADH and conditions causing metabolic alkalosis.
What affects the result
Rarely interpreted alone; read with sodium, CO2 and anion gap.
Units and conversion
Usually reported in mmol/L.
- From mEq/L: multiply by 1 to get mmol/L
Also called on lab reports
Cl, Chloride, Serum, Cl-
Related tests: Electrolytes & Minerals
This page is educational and does not replace advice from a healthcare professional.