Electrolytes
This test measures essential electrolytes that regulate fluid balance, nerve signalling and muscle function. It helps assess hydration, kidney health and metabolic stability.
Turnaround time
Results available 4 hours after arrival in lab. Doctor's report sent the day after results available (if required)
Biomarkers count
4
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Details about Electrolytes
What is the Electrolytes Test?
The Electrolytes test measures key minerals in the blood that carry an electrical charge and are vital for normal bodily function. These electrolytes help regulate fluid balance, nerve impulses, muscle contraction and acid–base balance.
Electrolyte levels are tightly controlled by the kidneys and hormonal systems. Even small imbalances can cause significant symptoms, making this test essential in both routine health assessments and acute medical evaluation.
The test is commonly used as part of general health screening and in the investigation of dehydration, kidney disease and metabolic disorders.
Why do I need an Electrolytes test?
You may need this test if you have symptoms suggestive of fluid or mineral imbalance or if you are being monitored for kidney, heart or endocrine conditions. Electrolyte disturbances can occur due to illness, medication use, dehydration or excessive fluid intake.
Testing helps identify imbalances early, allowing prompt correction and prevention of complications such as cardiac rhythm disturbances or neurological symptoms.
Symptoms and scenarios where testing is recommended:
- Dehydration or fluid overload
- Muscle cramps or weakness
- Irregular heartbeat
- Confusion or dizziness
- Kidney disease monitoring
- Diuretic or blood pressure medication use
- Vomiting or diarrhoea
- Routine health screening
What’s Tested in This Profile?
- Sodium
- Potassium
- Chloride
- Bicarbonate
Benefits of the Electrolytes Test
- Assesses hydration status
Identifies dehydration or fluid imbalance. - Supports kidney function evaluation
Electrolytes reflect renal regulation efficiency. - Monitors heart rhythm risk
Potassium and sodium are critical for cardiac function. - Detects acid–base disturbances
Bicarbonate helps assess metabolic balance. - Guides medication management
Important for patients on diuretics or ACE inhibitors. - Supports acute illness assessment
Essential in emergency and inpatient care. - Useful in chronic disease monitoring
Tracks electrolyte stability over time. - Simple but clinically powerful test
Provides rapid insight into metabolic health.
Step-by-Step: How Testing Works
Choose your preferred testing method
You can attend one of our UK partner clinics or arrange a home or hotel visit with a mobile phlebotomist.
Option 1 – In-Clinic Blood Draw
- Select your nearest UK clinic and book an appointment.
- A clinician or phlebotomist collects a venous blood sample.
- The sample is analysed for electrolyte levels.
- Results are delivered securely online.
Option 2 – Home or Hotel Phlebotomy (+£60)
- Book a UK-wide home or hotel visit at a convenient time.
- A trained phlebotomist collects your blood sample on-site.
- The sample is transported to the laboratory.
- Results are uploaded digitally without the need to travel.
Your Results Explained
Low Levels
Low sodium or potassium may indicate dehydration, kidney dysfunction or hormonal imbalance.
Low potassium can increase the risk of muscle weakness and heart rhythm disturbances.
Typical UK reference ranges vary by electrolyte and laboratory.
Normal Levels
Normal electrolyte levels suggest stable fluid balance, kidney function and metabolic control.
This supports healthy nerve and muscle activity.
High Levels
Elevated electrolytes may indicate dehydration, kidney disease or medication effects.
High potassium or sodium requires prompt medical review due to cardiac risk.
How It Works
Simple steps to get your results
Book Online
Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
Take control of your health with London Blood Tests
WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.