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Electrolytes

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Created: 28/02/2024
Edited: 02/02/2026
Written by: Carlota Pano

What is analysed?

Electrolytes are essential ions in the body that carry an electric charge and play an important role in various physiological functions, including fluid balance inside and outside cells.

The major electrolytes in the body include:

  • sodium (Na+)
  • potassium (K+)
  • chloride (Cl-)
  • bicarbonate (HCO3)
  • calcium (Ca2+)
  • phosphate (HPO4^2- and H2PO4^-)

The electrolyte test measures the level of electrolytes in body fluids, such as blood.

What does the result mean?

The result indicates the concentration of electrolytes in the body.

Why conduct the analysis?

The electrolyte test is conducted to help diagnose conditions such as dehydration, kidney disorders, and heart conditions.

When to conduct the analysis?

The electrolyte test is conducted in various clinical scenarios:

  • Routine health check ups
  • Emergency situations
  • When specific symptoms are observed, such as excessive thirst, muscle weakness, irregular heartbeat, and mental health symptoms

What sample is required?

A blood sample is required. The blood is drawn from a vein, usually in the arm.

In some cases, a urine sample may also be analysed for specific electrolytes.

Is any prior preparation necessary?

Patients should fast 8-12 hours before the sample is taken.

How is it performed?

The sample is sent to a laboratory, where it is analysed using ion-selective electrodes or colorimetry techniques to measure the concentrations of electrolytes.

What are the normal values?

Electrolyte

Normal range

Sodium (Na)

135 to 145 mEq/L

Potassium (K)

3.5 to 5.0 mEq/L

Chloride (Cl)

95 to 105 mEq/L

Bicarbonate (HCO3)

22 to 28 mEq/L

Calcium (Ca)

8.5 to 10.5 mg/dL

Phosphate (PO4)

2.5 to 4.5 mg/dL

What does having altered values mean?

  • Low sodium levels (hyponatraemia): Indicate dehydration, kidney problems, or hormonal imbalances, which can lead to confusion, seizures, and nausea.
  • High potassium levels (hyperkalaemia): Indicate kidney problems or the use of certain medications, which can lead to muscle weakness, heart palpitations, and cardiac arrhythmias.
  • Low calcium levels (hypocalcaemia): Indicate hypoparathyroidism or malabsorption, which can lead to muscle spasms, tingling sensations, and seizures.
  • High phosphate levels (hyperphosphataemia): Indicate kidney problems, which can lead to muscle cramps and bone pain.
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