Chloride optimal range and reference range
Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026
Sera's bands for Chloride:
- Optimal 100 – 106 mEq/L (100 – 106 mmol/L); sufficient 98 – 108 mEq/L (98 – 108 mmol/L); out of range below 98 or above 108 mEq/L.
Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.
All units
| Unit | Optimal | Sufficient | Out of range |
|---|---|---|---|
| mEq/L | 100 – 106 | 98 – 108 | below 98 or above 108 |
| mmol/L | 100 – 106 | 98 – 108 | below 98 or above 108 |
What the evidence says
The acceptable band runs from the US laboratory lower limit of 98 mmol/L (MedlinePlus, Mayo Clinic Laboratories) to the UK harmonised upper limit of 108. US laboratories usually stop at 107 and UK laboratories start at 95, so the range printed on the report may differ by a unit or two. The optimal band of 100 to 106 is a functional target with no published evidence behind it. Chloride is read with sodium and bicarbonate rather than on its own.
Sources
- Chloride test - blood — MedlinePlus Medical Encyclopedia, U.S. National Library of Medicine, 2025 · Government / public-health guidanceTypical normal range 98 to 107 mEq/L. Matches Sera's lower edge of 98; the upper limit is one unit below Sera's 108.
- ELPSR - Overview: Electrolyte Panel, Serum — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceAdult serum chloride reference values: 98 to 107 mmol/L. Same interval as MedlinePlus.
- Chloride (Pathology tests database) — University Hospitals Birmingham NHS Foundation Trust, 2026 · Laboratory / reference-interval sourceUK harmonised interval (Pathology Harmony) 95 to 108 mmol/L. Matches Sera's upper edge of 108.
What Chloride measures
A major electrolyte that works with sodium to control fluid balance, blood pressure, and the body's acid-base balance.
Abnormal levels can point to dehydration, kidney problems, or metabolic disorders.