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Electrolytes Blood Test

Original price £59.00 - Original price £59.00
Original price
£59.00 - £59.00
Current price £59.00

Take this test to monitor the levels of vital salts and minerals like sodium and calcium in your bloodstream, that impact nerve impulse conduction, muscle contractions, and blood acid-base balance.

  • Biomarkers: 4
  • Turnaround: 1-2 days

Simple and accurate blood test from a laboratory you can speak to.

Step 1. Choose sample collection option

Currently selected option: HOME KIT via Royal Mail Tracked 24

  • Available everywhere in mainland UK.
  • Includes everything you need to take a safe and suitable blood sample in about 15 minutes.
  • Post the sample back to our laboratory via Royal Mail Tracked 24.

Re-test guarantee

Our Electrolytes Blood Test

Understand your body's core biological functions with our Electrolytes Blood Test. By monitoring the levels of vital salts and minerals like sodium, potassium, and calcium in your bloodstream, this test provides insights into your body's nerve impulse conduction, muscle contractions, and blood acid-base balance.

Essential for individuals with specific health conditions or taking certain medications, our test combines the convenience of at-home sample collection with the reliability of our regulated laboratories. 

Save on continuous monitoring with our subscription discounts and see panel-level commentary on our free Health Dashboard tool. Choose One Day Tests for fast, accurate results that empower you to take control of your health.

About the Electrolytes Blood Test

Electrolytes, the salts and minerals in our bloodstream, play a vital role in nerve impulse conduction, muscle contractions, and maintaining the blood's acid-base balance. These include sodium, potassium, and calcium, fundamental for our body's biological functions, including heart rhythm maintenance.

Significant electrolyte imbalances are uncommon in generally healthy individuals. They occur more frequently in hospitalised patients or those with kidney disease, severe diarrhoea or vomiting, as well as those in malnourished states, potentially caused by eating disorders.

Electrolyte imbalances can also be a side effect of certain medications, notably those used for blood pressure control. Regular monitoring is standard for individuals on these medications, as any imbalance typically resolves itself once the medication is discontinued.

4 Biomarkers


    - Sodium
    - Calcium
    - Potassium (Clinic only. Not available in home kits as this biomarker can only be accurate if analysed within very short period of time < 8 hours.)
    - Chlorine


    Need more biomarkers? Check out our Advanced Electrolytes & Urea (U&E) Blood Test


    For most biomarkers our usual turnaround time is 24-48 hours, or less, from the time your sample is in our lab. We do not wait for all the results to complete before sending them to you, so you may start receiving results the same day for most cases, or as results become available.

    We are extremely proud of our very short turnaround times and a very efficient laboratory processes. Whilst we accommodate the shortest of time scales, with some results available within hours, for this particular test the usual turnaround time is:

    1-2 days

Doctor's notes

Hi, I am Dr. Adam Staten and here's my view on this test as a GP and Clinical Director at One Day Tests.

The importance of electrolytes can't be overstated. Yet, strangely, they're often overlooked despite being fundamental to our biology. Sodium, potassium, and calcium are critical for conducting nerve impulses, enabling muscle contractions, and maintaining heart rhythm. 

Thankfully, significant electrolyte abnormalities aren't common in generally healthy individuals, although they are more prevalent in those who are seriously ill in hospital. Such abnormalities can occur due to a range of conditions, with the more common causes being kidney disease, severe diarrhoea or vomiting, or malnourished states, including eating disorders.

Electrolyte imbalances, however, are a fairly common side effect of some medications, particularly those used for blood pressure control. Consequently, routine electrolyte monitoring is standard for individuals on these medications. The good news is, these abnormalities are typically mild and tend to correct themselves if the medication is discontinued.

Red flag symptoms for the Electrolytes Blood Test

  • Progressive weakness or lethargy
  • Confusion
  • Severe muscle cramps

Your Results and Health Dashboard

The results of your Electrolytes Blood Test will be emailed to you as a secured PDF file, ready for your GP and will also be uploaded to our Health Dashboard area of the website. It’s a unique and powerful tool, powered by our in-house clinical analysis research, to match your biomarkers across test panels and symptoms, as well as provide clinical commentary on all individual biomarkers you tested for.

The health dashboard will also provide "panel level" commentary - a birds eye view of the biomarkers that were tested. This feature allows you to view your test results and clinical commentary, and compare them to previous results, giving you a clear understanding of how your health is progressing.

By using the Health Dashboard, you can identify changes in your biomarkers and make necessary adjustments to your lifestyle. This added value is immense, as it empowers you to monitor your health and make informed decisions about your well-being.

It's free and is available with all of our tests.

Save on continuous monitoring with our subscription plan

The best way to look after your health is to do so regularly. This is easy to do with our continual monitoring plans which give you a discount on future blood tests. You choose the frequency and we'll do the rest.

When you purchase a subscription, we will deliver your home test kits or allow you to book appointments in line with your chosen frequency. You will be able to track your biomarkers over time in our powerful Health Dashboard, where results will be automatically updated for you. There is a minimum of 3 tests with any subscription, after which you can pause/restart/cancel at any time.

Special instructions

Hi, I am Stefania Brown, I am the Laboratory Manager at One Day Tests and here are the lab's special requests for the Electrolytes Blood Test.

There are no special instructions for this test.

We are not able to report on the potassium concentration in the home kit version of this test due to the unstable nature of potassium.

Venepuncture appointment - how to prepare

If you are coming into one of our clinics for the test, this is what you need to do before you arrive:

  • Drink plenty of water about an hour before the appointment.
  • Avoid coffee/tea/energy drinks. Water is good!
  • That’s it! We’ll do the rest.

Home test kit for Electrolytes Blood Test - how it works

Our blood test kits are simple and convenient.

The most important step in doing a blood test at home is to read the instructions very carefully. The process is very simple, but there are a few pitfalls you need to be aware of - you will save yourself a lot of time if you do it right the first time around!

  • Full printed instructions will arrive with your kit - please read them carefully.
  • Drink plenty before taking the sample and warm your hands up in the sink with warm water for a few minutes. This will make your blood flow much better.
  • Fill the tubes to the top line. We don’t need much blood; filling tubes to the top line is about 15 drops of blood.
  • Post the samples on the same day you take them, before midday, Monday to Thursday. If you post it any other time it might get to us late or be stuck at a sorting office over the weekend. You will then have to do it again.
  • Package the sample in the same box the kit came in. Otherwise, Royal Mail or DPD will reject it. The sample tubes go into a pouch, then into a cardboard box, and then into a return envelope. All of this is provided in the kit: please use it.

We look forward to receiving your sample in our lab!

How the finger prick home test kit for Electrolytes Blood Test works - from Dr. Adam Staten

Why choose us?

Hello! My name is Dr. Vinesh Mistry, I am part of the GP team here at One Day Tests and here is why you should trust us to test your blood.

We run our own regulated laboratories and our own accredited clinics. We manufacture our own approved home sample collection kits. Your results are looked after by our fantastic clinical governance team and our super-talented biomedical science team.

When you book your test with us - you book directly with the lab. This means accuracy and responsible duty of care, direct access to the provider and extremely fast turnaround times.

Finally, our customer services rock! You can ask the lab a question any time or you can speak to a real human. It's good to WhatsApp, email on or give us a call on 0845 527 07 67.

Frequently Asked Questions

Hi, I am Lana Nela, Lead Nurse, and here is what we are frequently asked about this test.

What are the symptoms of electrolyte imbalances?

This depends on the electrolyte that is either high or low. In many cases, if the imbalance is mild, there will be no symptoms. Major electrolyte imbalances can cause lethargy, muscle cramps, nausea, weakness, and eventually, severe problems such as seizures and cardiac arrest. 

If my medication can cause electrolyte imbalances, is it putting my health at risk?

It is routine practice to check people’s electrolytes soon after starting a medication that can affect the electrolytes, again after a dose change, and then yearly after that. This allows your doctor to identify any problems early and change the medication if necessary. 

Can diet affect electrolytes?

Electrolytes come from our food, and a normal diet will usually provide adequate amounts of sodium, potassium and chloride. In fact, the Western diet usually contains too much sodium. Dietary potassium is usually adequate, and you might be advised to avoid potassium-rich foods, such as tomatoes or bananas, if you are on a medication that can raise potassium levels. 

Low potassium levels can occur in malnourished states (as might occur in an eating disorder) or low levels might be a result of excess potassium loss through prolonged diarrhoea or due to certain medications. In these circumstances, you might be given potassium supplements or advised to increase your dietary intake.

Your kidneys will get rid of excess potassium and sodium, assuming they are healthy.

Your levels of calcium may be low if you eat little calcium, for example, if you follow a plant-based diet, and your calcium may also be low if your vitamin D levels are low.

Why take this test?

Hi, I am Dr. Marco Esposito and here is why it's important to take this test.
  • You want to see if your symptoms are due to an electrolyte imbalance
  • You want to check that your medications aren’t affecting your electrolytes

Is this test right for you?

Hi, I am Sandeep Patel, I am the Laboratory Director at One Day Tests. Here are the symptoms that you may wish to address with this test.

Electrolyte imbalances can be the result of a number of illnesses, dietary factors and, perhaps most commonly, medication.

You can take the electrolyte test to make sure that your levels of sodium, potassium, chloride and calcium are all normal.


    Abdominal discomfort, Chronic fatigue, Confusion, Convulsions or seizures, Diarrhoea, Fast beating heart, Fatigue, Headache, Irregular heartbeat, Irritability, Muscle cramps, Nausea, Stomach cramps, Tingling, and Vomiting

Why blood tests are important.