Clarity Labs
Login
Find your panel
Kidney Health

Chloride

Chloride is a charged mineral that shadows sodium almost everywhere it goes, helping to keep your body's fluids balanced and your nerve signals smooth and steady. It is nearly always measured as part of a group of minerals rather than on its own, and an in-range result simply means your fluid and salt balance is ticking along as it should.

Standard Care
CategoryKidney Health
Reference range95–110 mmol/L mmol/L
Evidence✓Standard Care
Last updated3 July 2026
On this page

What is chloride?

Chloride is an electrolyte — an electrically charged mineral that works closely alongside sodium and potassium. Where sodium and potassium are positively charged, chloride carries a negative charge, and that contrast is part of how cells keep their electrical balance: "sodium and potassium are positively charged, while chloride is negatively charged. Chloride follows sodium and when sodium moves into or out of cells, chloride follows to balance the electric charge." Beyond shadowing sodium, chloride has its own job in the nervous system. The RCPA describes it this way: "chloride is needed to help stabilise these electrical signals in cells. It stops nerves and muscles from firing too easily, helping to keep signals smooth and controlled." It also plays a role in acid-base (pH) balance — as the RCPA notes, "its level usually mirrors that of sodium."

Why is it tested?

Chloride is almost always tested as part of an electrolytes panel that also includes sodium, potassium, and bicarbonate. It is rarely ordered or interpreted on its own. Measuring it helps your GP assess fluid balance, kidney function, and acid-base status. Because chloride usually mirrors sodium, a reading that diverges from sodium can sometimes point to an acid-base disturbance worth investigating further.

Reference range (Australia)

95–110 mmol/L mmol/L

The AHRIA harmonised reference interval (AACB/RCPA-endorsed) applies to adults of all sexes. The range printed on your own report is the figure your GP will use for your result.

Reference intervals vary between laboratories. Always use the range printed on your own report.

What your result means

If your level is low

Chloride below the reference range (hypochloraemia) commonly reflects significant fluid losses — vomiting in particular causes chloride loss — or the effect of diuretic medicines (fluid tablets). Chloride also tends to be low when bicarbonate is high, because the two electrolytes move in opposite directions to keep your blood's acid-base balance steady. Because chloride usually tracks sodium closely, your GP will compare the two results to assess whether a divergence gives useful information about fluid or acid-base balance.

If your level is in range

An in-range chloride result, read alongside normal sodium and bicarbonate, suggests your fluid and electrolyte balance is well maintained. Staying hydrated and keeping your GP informed of any new medicines supports that balance over time.

If your level is high

Chloride above the reference range (a state called hyperchloraemia) most often accompanies dehydration or a low bicarbonate — the two tend to move in opposite directions when the blood becomes more acidic (a process called metabolic acidosis). Kidney conditions affecting how fluids are handled can also raise chloride. Your GP will interpret it alongside your other electrolytes, particularly sodium and bicarbonate, rather than as a standalone result.

What can affect your result

Chloride tends to move with sodium, so most things that raise or lower sodium have a similar effect on chloride. Dehydration concentrates both; excess fluid intake dilutes both. Vomiting is a notable exception — it causes significant chloride loss without necessarily the same sodium shift, because stomach acid is rich in chloride. Diuretics (fluid tablets) increase the amount of chloride passed in the urine and can lower the blood level. Kidney disease can impair the normal regulation of chloride. Acid-base balance and chloride are also linked: when the blood becomes too acidic or too alkaline, chloride shifts to help compensate.

When to act

Chloride rarely needs acting on by itself. If it is outside the usual range, your GP will look at the full electrolytes picture — sodium, potassium, and bicarbonate together — to understand whether the chloride finding is significant or simply reflecting something already accounted for by the other results. If you have symptoms such as persistent vomiting, unusual muscle weakness, or significant fatigue alongside an abnormal chloride, mentioning those to your GP adds important context. This page is general information and is not a substitute for advice from your GP.

Frequently asked questions

The harmonised reference interval endorsed by the AACB and the RCPA is 95–110 mmol/L for adults. Laboratories may set slightly different intervals, so the range printed on your own report is the one that applies to your result.

Chloride carries a negative electric charge, while sodium carries a positive one. When sodium moves in or out of cells — as it constantly does to manage fluid and send nerve signals — chloride follows to balance the electric charge. This is why chloride levels usually mirror sodium levels, and why the two are nearly always read together.

Almost always as part of a panel. Chloride is one of four electrolytes — alongside sodium, potassium, and bicarbonate — that are measured together to assess fluid balance, kidney function, and acid-base status. A chloride result in isolation is rarely meaningful; it is the pattern across all four that your GP uses to build a picture.

Low chloride (hypochloraemia) most often reflects fluid losses, particularly from vomiting, or the effect of diuretic medicines. Because stomach acid contains a high concentration of chloride, prolonged vomiting can cause a more marked chloride loss than other types of fluid loss. Your GP will look at your sodium and bicarbonate alongside the chloride to understand the cause.

Yes. When you are dehydrated, the amount of fluid in your blood decreases, which concentrates the electrolytes in it — including chloride. This can push the result above the reference range. Rehydrating usually brings it back within range, and your GP may recommend a repeat test after you are well hydrated if dehydration was a likely factor.

Test your chloride

NATA-accredited testing. Results in 2–5 days. No GP referral required.

View UEC