What is this test?
Chloride is a major negatively charged electrolyte that works with sodium and bicarbonate to maintain fluid and acid-base balance.
Why might it be ordered?
- To assess dehydration, vomiting, kidney problems or an acid-base disturbance.
- As part of electrolyte monitoring during illness or treatment.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Ask the laboratory whether you need to fast or attend at a particular time. Do not stop or change medicines or supplements unless your clinician tells you to.
How should you understand the result?
Chloride usually changes in relation to sodium and bicarbonate. A high or low value alone rarely identifies the cause.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.