Sodium Blood Test -- Assess Fluid and Electrolyte Balance
Sodium is present in all body fluids, with the highest concentrations in the blood. It works with potassium and calcium to maintain proper cell function and fluid balance. The body tightly regulates sodium through hormonal mechanisms and the thirst response. A sodium blood test reveals whether these regulatory systems are working as they should.
Why Test Sodium?
Testing sodium is essential for managing health risks related to diet and lifestyle. A high intake of processed foods, sodium, and alcohol can disrupt balance. Regular testing monitors changes as you adjust your lifestyle, take supplements or medications, or manage conditions such as dehydration, high blood pressure, or oedema. Athletes should also monitor sodium for optimal performance.
What Do High Sodium Levels Mean?
High sodium (hypernatraemia) is nearly always caused by dehydration -- not replacing lost water sufficiently. Rarely, it can result from excessive salt intake, Cushing syndrome, or diabetes insipidus. Certain medications, including corticosteroids, anabolic steroids, and oral contraceptives, can also raise sodium.
What Do Low Sodium Levels Mean?
Low sodium (hyponatraemia) is more common and can result from excessive sweating, diarrhoea, diuretic use, endurance exercise, or excess water intake. Serious underlying conditions include heart failure, liver cirrhosis, kidney damage, and adrenal insufficiency. It is more prevalent in the elderly.
Symptoms to Watch For
- Confusion or irritability
- Headache
- Nausea or vomiting
- Muscle weakness or cramps
- Extreme thirst (high sodium)
- Seizures in severe cases
Who Should Get Tested?
- People with high blood pressure or heart disease
- Those on diuretics or blood-pressure medications
- Endurance athletes
- Individuals experiencing dehydration, swelling, or confusion
- Elderly people at higher risk of hyponatraemia
How to Prepare for Your Test
No preparation is needed. Bring valid ID to your appointment.
Order Your Blood Test
Test your Sodium levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
Can drinking too much water lower sodium?
Do medications affect sodium levels?
How is sodium related to blood pressure?
Reviewed by
Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
Learn more about our team →Medical Disclaimer
The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.