The Aldosterone Blood Test measures aldosterone, a hormone that regulates blood pressure, sodium, and potassium balance. It is commonly used to investigate unexplained high blood pressure, low potassium, and suspected adrenal or hormonal disorders. Testing is performed in a UKAS-accredited laboratory, with an optional GP consultation.

What is an Aldosterone Blood Test?

Aldosterone is a hormone produced by the adrenal glands that helps control blood pressure by regulating sodium and potassium levels in the blood. It acts on the kidneys to increase sodium and water retention while promoting potassium excretion.

Abnormal aldosterone levels can lead to:

• Persistent or treatment-resistant high blood pressure
• Electrolyte imbalances
• Fatigue, muscle weakness, or cramps

The Aldosterone test is often used to assess for primary aldosteronism (Conn’s syndrome) or secondary causes of hormonal imbalance. It may also be measured alongside renin as part of an aldosterone-renin ratio (ARR) investigation.

At London Blood Tests, aldosterone is measured using validated immunoassay techniques aligned with UK endocrinology standards.

Benefits of the Aldosterone Test

1. Investigates Hormonal Causes of High Blood Pressure
   Helps identify endocrine-driven hypertension.
2. Detects Adrenal Gland Disorders
   Supports diagnosis of aldosterone overproduction.
3. Assesses Electrolyte Imbalance Causes
   Useful in low potassium or sodium abnormalities.
4. Guides Targeted Treatment Decisions
   Helps tailor medication or referral to specialists.
5. Supports Resistant Hypertension Evaluation
   Valuable when blood pressure remains high despite treatment.
6. Non-Invasive & Accurate
   Simple blood test with high clinical relevance.
7. Optional GP Consultation for Interpretation
   Results reviewed with a GP for next-step guidance.

Why Do I Need an Aldosterone Blood Test?

You may benefit from this test if you:

• Have high blood pressure, especially at a young age
• Have hypertension that does not respond to medication
• Have low potassium levels
• Experience muscle weakness or cramps
• Have an adrenal nodule detected on imaging
• Want to investigate hormonal causes of blood pressure changes

Symptoms associated with abnormal aldosterone include:

• Persistent high blood pressure
• Fatigue
• Muscle weakness
• Frequent urination
• Headaches

Because hormonal causes of hypertension are often overlooked, aldosterone testing supports accurate diagnosis and management.

How the Test Works

In-Clinic Testing at London Blood Tests

1. Book Your Appointment
• Online or phone booking
• Preparation may be required (medications and posture can affect results)
2. Pre-Test Guidance
• Inform the clinician about blood pressure medications
• You may be asked to sit or rest before sampling
3. Sample Collection
• Venous blood sample collected by a trained phlebotomist
• Takes 5–10 minutes
4. Laboratory Analysis
• Tested in a UKAS-accredited laboratory
5. Quality Control
• Results validated before release
6. Results Delivery
• Results typically available within 5-6 business days
7. Optional GP Consultation
• Review hormone levels and further testing needs

At-Home Blood Draw (Home or Hotel Phlebotomy – UK-Wide)

1. Book a Phlebotomist Visit
• Home or hotel blood draw arranged
2. Professional Collection
• Sample collected following posture guidelines
3. Secure Transport
• Sample couriered same day
4. Laboratory Testing
• Identical analysis to clinic testing
5. Results & Follow-Up
• Results delivered online, GP review optional

Your Aldosterone Test Results – Explained

Aldosterone results are usually reported in pmol/L.

Typical UK reference guidance (may vary by posture):

• Upright: ~ 100–800 pmol/L
• Supine: ~ 70–550 pmol/L

Interpretation:

• High aldosterone: primary aldosteronism, adrenal overactivity
• Low aldosterone: adrenal insufficiency, certain medications
• Normal aldosterone: hormone regulation likely intact

Results are often interpreted alongside renin, potassium, sodium, and blood pressure readings.