Aldosterone blood test in Chiswick

What the test measures

Aldosterone is made by the outer layer of the adrenal glands, which sit above the kidneys. It tells the kidneys to hold on to sodium and water and to release potassium, which in turn helps set blood volume and blood pressure. Its release is controlled mainly by renin, an enzyme from the kidneys, so the two are often interpreted together.

When the adrenal glands make too much aldosterone on their own, a condition called primary aldosteronism or Conn's syndrome, blood pressure rises and potassium can fall. This is one of the more common treatable causes of high blood pressure and is worth looking for in the right people. Too little aldosterone, as in Addison's disease, is less common and can cause low blood pressure, salt craving and tiredness.

The price 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.

Who it is for

• You have high blood pressure that remains high despite several medicines.
• You developed high blood pressure at a young age.
• Your potassium has come back low, with or without high blood pressure.
• You have symptoms such as muscle weakness, cramps or frequent urination alongside high blood pressure.
• Your GP or specialist has asked for aldosterone as part of an adrenal assessment.

Understanding your result

Your report shows the laboratory reference range, but aldosterone is rarely read on its own. Specialists usually compare it with renin as an aldosterone to renin ratio, because a high aldosterone with a suppressed renin is the pattern that suggests primary aldosteronism. A single raised level can also reflect posture, salt intake, low fluids or medicines, and a low level may point to adrenal underactivity.

A result outside the range is a prompt for discussion, not a diagnosis. Confirmation is normally carried out by an endocrinology team, and your practitioner can help you prepare for that conversation with your GP.

Preparing for your test

No fasting is needed. Aldosterone varies with time of day and posture, so a mid-morning appointment is preferred, after you have been up and about for at least two hours, then seated for a few minutes before the sample. Several blood pressure medicines, diuretics, the contraceptive pill and liquorice can alter results. Do not stop any prescribed medicine without speaking to your doctor, and tell us what you take when you book.

Because aldosterone works through the kidneys, our kidney and electrolyte tests, which include potassium and sodium, are a helpful companion. Our cortisol test looks at another adrenal hormone. Browse every blood test and price in Chiswick.

Questions

How much is an aldosterone test in Chiswick?

The Aldosterone test costs £199 at our Chiswick clinic. It includes the blood sample, accredited laboratory analysis, a practitioner review and a GP feedback report on request.

Should I stop my blood pressure tablets before testing?

No, not without medical advice. Some medicines affect the result, but stopping them can be unsafe. Your GP or specialist will advise whether any changes are needed.

What is the aldosterone to renin ratio?

It compares the two hormones to see whether aldosterone is being made independently of the normal control system. It is the usual screening approach used by specialists for primary aldosteronism.

Can stress affect aldosterone?

Acute stress and illness can raise it temporarily, which is one reason results are read in context and sometimes repeated.