Sodium

Clinical Chemistry

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Description

For advice about causes, investigation and management of hyponatraemia, see clinical chemistry guidelines available via the CCG portal. Sodium is the major extracellular cation and functions to maintain fluid distribution and osmotic pressure. Sodium also plays an important role in maintaining the electrical potential across the cell membrane, which is essential for muscle and nerve action. Sodium intake is via the diet and excretion is mainly renal. In health there is a small amount of loss throught the GI tract and skin.

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Indications

Serum 1. Diagnosis and monitoring of patients with abnormal fluid status. 2. Monitoring patients on medications known to cause sodium abnormalities. 3. Investigation of patients with unexplained central neurological symptoms or signs. Urine 1. Investigation of hyponatraemia. 2. Investigation of oliguria. 3. Assessment of dietary sodium intake.

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Sample Type

Serum, SST/Gel, minimum 2mL (1mL separated serum). Plain urine (No preservative)

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Within 1 day

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Testing Frequency

As Required

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External Notes

Hyperproteinaemia or Hypertriglyceridaemia may cause pseudohyponatraemia. This can be avoided by measuring sodium using a Direct Ion Selective Electrode (ISE) on a blood gas analyser.

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.