Chloride · high result
High chloride levels: causes, symptoms and what to do
Short answer
Chloride is the main negative ion in blood and moves with sodium and bicarbonate, so a high level — above about 106 to 107 mmol/L — is read with those two rather than on its own. Most often it means the body is short of water (dehydration, usually with a high sodium) or that bicarbonate has fallen and chloride has risen to fill the gap, a pattern called a normal-anion-gap metabolic acidosis: diarrhea, early kidney disease, renal tubular acidosis and a few medications do this. Salt in the diet does not. A mildly high chloride with normal sodium, bicarbonate and kidney function is rarely significant.
Medically reviewed by Youmna DiStefano, MD · Last reviewed October 2026
When does this result need same-day care?
- High chloride with a high sodium and confusion, extreme thirst or very little urine — significant dehydration, same-day care, especially in older adults and infants
- Rapid deep breathing, vomiting and drowsiness with a low bicarbonate — significant acidosis
- Ongoing diarrhea or vomiting with dizziness or fainting
What is the normal range for Chloride?
- age 18+: 98.0 – 107 mmol/L
Full reference table, citations and testing options: Chloride biomarker page.
What are the common causes of high Chloride?
- Dehydration — vomiting, diarrhea, heavy sweating, too little fluid, diabetes insipidus or poorly controlled diabetes; sodium is usually high too and both fall with fluids
- Loss of bicarbonate through the gut — prolonged diarrhea, laxative overuse, an ileostomy or urinary diversion; chloride rises as bicarbonate (CO2) falls
- Kidney causes of acidosis — renal tubular acidosis, early chronic kidney disease, and the recovery phase after acute kidney injury
- Medications — acetazolamide and other carbonic anhydrase inhibitors (including some glaucoma drops), high-dose aspirin, ammonium chloride, some steroids and androgens, and large volumes of normal saline in hospital
- Compensation for chronic over-breathing (respiratory alkalosis) — anxiety, pain, pregnancy, high altitude, liver disease; the kidneys shed bicarbonate and keep chloride
- Hyperparathyroidism, which tends to raise chloride slightly and lower bicarbonate
- Bromide-containing medications or supplements, which the lab measures as chloride — a false high rather than a true one
What symptoms go with high Chloride?
- Usually none — a high chloride is almost always found on a metabolic panel ordered for another reason
- Of dehydration: thirst, dry mouth, dark and scanty urine, dizziness on standing, headache
- Of acidosis when it is marked: deeper or faster breathing, fatigue, weakness, nausea and poor appetite, confusion in severe cases
- Of the kidney or gut condition behind it
What do clinicians usually check next?
- Read sodium, CO2 (bicarbonate), potassium, BUN and creatinine from the same panel and calculate the anion gap (sodium minus chloride minus bicarbonate; normal roughly 8–12) — high chloride with a low bicarbonate and a normal gap is the acidosis pattern; high chloride with a high sodium is the dehydration pattern
- Repeat well-hydrated if dehydration is likely; most mild elevations disappear on the second draw
- Review medications, eye drops and supplements for carbonic anhydrase inhibitors, salicylates and bromide
- If bicarbonate is persistently low: a urine pH and urine anion gap to distinguish gut loss from renal tubular acidosis, plus a kidney-function trend and urinalysis
- A blood gas when breathing is abnormal or acidosis is more than mild, to confirm whether the primary problem is metabolic or respiratory
- A chloride that is high by only one or two points with everything else normal needs no further testing
How do you recheck Chloride?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Basic Metabolic Panel | Test · 8 biomarkers | $17.99 | Yes | 1–3 business days |
Common questions
What is a high chloride level?
Above the lab's reference range, which usually tops out between 106 and 107 mmol/L (some labs 108–110). A reading one to three points over the line is common, often reflects mild dehydration at the time of the draw, and is not meaningful if sodium, bicarbonate and kidney function are normal. Values above about 110–115 mmol/L, or a high chloride paired with a low bicarbonate or a high sodium, point to a real disturbance in fluid or acid-base balance that needs explaining.
Is a high chloride level from eating too much salt?
Not in a person with working kidneys. Table salt is sodium chloride, but the kidneys adjust how much of both they excrete within hours, so the blood level reflects water balance and acid-base balance rather than the salt shaker. A high-salt diet raises blood pressure and makes you retain water; it does not push blood chloride above range. The exceptions are very large intakes of salty fluids in someone who cannot excrete them — mainly a hospital setting with saline infusions.
What does high chloride with low CO2 mean?
A normal-anion-gap (hyperchloremic) metabolic acidosis: the body has lost bicarbonate, and chloride has risen to keep the total negative charge in balance. The common causes are diarrhea, renal tubular acidosis, early chronic kidney disease, acetazolamide and large saline infusions. The anion gap on your panel (sodium minus chloride minus CO2) stays in the normal 8–12 range in this pattern, which is what separates it from the high-gap acidoses such as diabetic ketoacidosis or kidney failure.
What chloride level is dangerous?
The chloride number itself is rarely the danger; it is a marker of the fluid or acid-base problem behind it. Levels above about 115 mmol/L are unusual and almost always accompany severe dehydration with a high sodium or a significant acidosis, both of which produce symptoms — confusion, rapid breathing, weakness, very little urine — and need prompt treatment of the cause. A high chloride with no symptoms and normal companions is not dangerous.
How do you lower high chloride?
By treating what raised it. If the cause is dehydration, drinking water (or intravenous fluids when oral intake is not possible) brings chloride and sodium back together. If the cause is bicarbonate loss, treating the diarrhea or kidney problem — and in renal tubular acidosis, prescribed bicarbonate or citrate — corrects it. Stopping or switching a causative medication such as acetazolamide works within days. There is no diet or supplement that lowers chloride directly, and none is needed.
My chloride is 108 — should I worry?
Probably not. 108 is at or just above the upper limit at most labs and is a common finding after a fasting morning draw, a hot day or a workout. Look at the companions on the same panel: if sodium is normal, CO2 (bicarbonate) is normal and creatinine is normal, the sensible step is simply a repeat when well hydrated. If bicarbonate is low (under 22) or sodium is high (over 145), the pattern deserves a conversation with a clinician about acid-base balance or fluid status.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.