Sodium blood test in Chiswick

What the test measures

Sodium is the most plentiful electrolyte in the fluid outside cells. It governs how water moves around the body, helps keep blood pressure steady and is needed for nerves and muscles to work. The blood level depends less on how much salt you eat and more on the balance between sodium and water, which is managed by the kidneys and by hormones such as antidiuretic hormone and aldosterone.

Sodium is usually read alongside potassium, urea, creatinine and eGFR. Together they give a picture of kidney function and fluid balance.

Your price includes the sample taken at our Chiswick clinic, analysis at the Randox accredited laboratory, a practitioner review of your result and a GP feedback report on request. No GP referral is needed.

Who it is for

• You take diuretics, some antidepressants or anti-epileptic medicines that can lower sodium.
• You are an older adult and have had confusion, unsteadiness or falls that your doctor wants to look into.
• You do endurance sport and drink large volumes of water during long events.
• You have reduced kidney function, heart failure or a liver condition and need routine monitoring.
• You have had vomiting or diarrhoea and want to check your electrolytes have recovered.

Understanding your result

A low sodium, called hyponatraemia, usually means there is too much water relative to sodium. It is commonly linked to diuretics and some other medicines, drinking very large amounts of fluid, heart, liver or kidney conditions and some hormone conditions. A raised sodium, called hypernatraemia, most often reflects too little water, for example through dehydration or not drinking enough. Mild changes are common and often settle once the cause is addressed.

Your report shows the laboratory reference range. A result outside it is a prompt for discussion with your practitioner, not a diagnosis. Anyone who becomes confused, drowsy or has a seizure needs urgent medical care through 999.

Preparing for your test

No fasting is needed. Drink as you normally would, without forcing extra water or restricting fluids, so the result reflects your usual balance. Keep taking your medicines as prescribed and tell us about them when you book, particularly diuretics and antidepressants. Avoid long endurance exercise on the day of the test.

Sodium is part of the Kidney Health Check, which covers the full set of urea and electrolytes with eGFR, and of the Standard Screen. You can also browse every blood test and price in Chiswick.

Questions

How much is a sodium blood test in Chiswick?

A sodium blood test costs £49. The price includes your sample at our clinic, laboratory analysis, a practitioner review and a GP feedback report on request.

Does eating more salt raise my blood sodium?

Not usually. Healthy kidneys remove extra sodium, so blood levels stay steady. High salt intake matters more for blood pressure than for the blood sodium result.

Can drinking too much water lower my sodium?

Yes, particularly during long endurance events or with certain medicines. Drinking to thirst is generally the safer approach.

Should sodium be tested on its own?

It can be, but it is more informative alongside potassium and kidney markers, which is why many people choose a kidney panel.