Serum Electrolytes
Electrolytes are the salts that keep nerves firing, muscles contracting and fluid where it belongs. They sit inside narrow ranges, and both the size of a change and the SPEED of it matter — a sodium that fell over hours is far more dangerous than the same sodium reached over weeks.
This is an educational reading aid, not a diagnosis and not medical advice. Reference ranges differ between laboratories — always read the range printed on your own report. Nothing here can see you, your history or your medicines. Do not start, stop or change any treatment on the strength of this page: take your report to a qualified doctor.
Reference ranges reviewed by Dr. Mohan Gayenlast reviewed
Your values
Fill in only the ones on your report. Anything you leave blank is simply skipped.
The main salt outside cells; it governs how water is distributed in the body.
Mostly inside cells. The heart is very sensitive to it in both directions.
Moves largely with sodium; used in working out acid–base problems.
The blood’s main buffer against acid.
Bone, nerve and muscle all depend on it. Read alongside albumin.
Needed for muscle and nerve function, and for keeping potassium and calcium in range.
Works with calcium in bone; handled by the kidneys.
Enter one or more values and your reading will appear here.
What this panel is easy to get wrong
- A HIGH POTASSIUM IS OFTEN AN ARTEFACT. If the sample was squeezed, shaken or left standing, potassium leaks out of the cells and the result is falsely high. A genuinely high potassium is usually repeated urgently rather than acted on blind.
- Potassium and calcium outside their critical bands affect the heart. These are the two on this panel that can be immediately dangerous.
- Calcium must be interpreted alongside albumin — a low albumin lowers total calcium without lowering the active (ionised) calcium at all. Corrected calcium or an ionised calcium is what a doctor will use.
Where these ranges come from: Commonly published adult intervals; critical bands follow widely used laboratory critical-value limits.
Where this is written from: This site is written from Indian clinical practice. Drug availability and brand names, vaccination schedules, national health programmes and some reference cut-offs differ between countries — a schedule or a threshold that is standard here may not be standard where you are. If you are reading outside India, check anything on this page against your own country’s guidance before you act on it.
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Sodium, potassium, chloride, bicarbonate, calcium, magnesium, phosphate.