Red cell potassium blood test in Chiswick

What the test measures

Potassium is an electrolyte that keeps nerves firing, muscles contracting and the heart beating in a steady rhythm. Most of it sits inside cells, and only a small fraction circulates in the blood. Good sources include fruit and vegetables, potatoes, beans, nuts and dairy.

In the NHS, potassium is measured in serum as part of a kidney and electrolyte profile, and that result guides medical decisions. Red cell potassium measures the potassium held inside red blood cells instead. It is not a routine NHS test and its interpretation is less established, so it is best treated as additional information read alongside serum potassium and kidney function rather than a test on its own.

The 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.

Who it is for

• You take diuretics, laxatives or other medicines that can affect potassium and want to discuss your levels.
• You have muscle weakness or cramps and are exploring nutritional factors with a practitioner.
• You follow a very low-carbohydrate, fasting or restrictive eating pattern.
• You have had a serum potassium result and would like an extra measurement for comparison.

Understanding your result

Your report shows your red cell potassium alongside the laboratory reference range. A lower or higher level may relate to diet, medicines or fluid balance, but because serum potassium is what doctors use to guide treatment, your practitioner will generally recommend checking serum potassium and kidney function if anything looks unusual.

A result beyond the range calls for a conversation with your practitioner rather than a conclusion. Palpitations, a very irregular heartbeat or sudden severe muscle weakness need urgent medical attention through NHS 111 or 999, not a routine blood test.

Preparing for your test

Fasting is not required for this test. Please avoid heavy exercise just before your appointment and tell us about any diuretics, blood pressure medicines, potassium supplements or salt substitutes you use. We go through any remaining preparation with you at booking.

Potassium is usually assessed together with kidney health, so our kidney and electrolyte tests are a natural companion. For diet-related markers, see Nutritional and Digestive Health or every blood test and price in Chiswick.

Questions

How much is a red cell potassium test in Chiswick?

The Red Cell Potassium test costs £99. It includes the blood sample at our Chiswick clinic, analysis at the Randox accredited laboratory, a practitioner review of your result, and a GP feedback report on request.

How does this differ from the usual potassium test?

The usual test measures potassium in serum and is part of a kidney and electrolyte profile. This test measures potassium inside red cells and is a complementary measure.

Can my blood pressure tablets change potassium?

Yes. Some diuretics lower potassium and some other blood pressure medicines raise it. Keep taking your medicines and discuss any result with your GP.

Should I eat more bananas if my result is low?

Your practitioner will look at the full picture first. Do not take potassium supplements without medical advice, as too much potassium can be dangerous.