Minerals

Sodium Blood Test

Sodium is a vital electrolyte that regulates fluid balance, blood pressure, and nerve and muscle function. It is the primary cation in extracellular fluid and is closely regulated by the kidneys.

Turnaround 48 hours, estimate Turnaround: up to 48 hours after your blood draw (estimate).

Reference Ranges

See the value that applies to you:

Age years

Choose male or female — this range differs by sex.

Enter your age — this range changes with age.

This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

Your reference range

mmol/l

136 145 mmol/l

Reference ranges by group, in mmol/l
Age	Reference range (mmol/l)	Relative scale
1 years and older	136–145 mmol/l	136 145

136 145 mmol/l

Source: NVKC Reference population: Dutch general-practice population (NUMBER, n = 7,574,327)

Reference values can vary between laboratories. Discuss your results with your GP for explanation and treatment decisions.

Sodium: what this test measures

This test measures the concentration of sodium in your blood. It helps assess hydration status, kidney function, and electrolyte balance.

Sodium: why this value matters

Sodium balance is essential for proper nerve transmission, muscle contraction, and blood pressure regulation. Significant imbalances can affect brain function and require medical attention. Consult your healthcare provider for guidance.

Sodium: how the blood test works

Referral: No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw: A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Results: Turnaround: up to 48 hours after your blood draw (estimate).
Where: 650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Sodium: when is testing worthwhile?

Testing is commonly included in routine blood panels. It may also be recommended if you take diuretics, experience confusion, have kidney disease, or show signs of dehydration or overhydration.

Sodium: symptoms of a high or low value

Low Levels

Low sodium (hyponatraemia) may cause headache, nausea, confusion, fatigue, muscle cramps, and in severe cases, seizures. It requires prompt medical evaluation.

High Levels

High sodium (hypernatraemia) may cause excessive thirst, restlessness, confusion, and in severe cases, neurological symptoms. It is often related to dehydration.

Sodium: lifestyle and this value

Maintain balanced salt intake and stay well-hydrated. Excessive salt consumption may contribute to high blood pressure. Be mindful of sodium content in processed foods.

Sodium: frequently asked questions

How much sodium should I consume daily?

Most guidelines recommend limiting sodium intake. However, individual needs vary based on health conditions and activity level. Your healthcare provider can offer personalised guidance.

Can drinking too much water lower sodium?

Yes, excessive water intake without electrolyte replacement can dilute blood sodium levels (hyponatraemia), especially during prolonged exercise.

Is all salt bad for health?

Sodium is essential for health — the concern is excessive intake. A moderate, balanced approach to salt consumption is generally recommended. Discuss your needs with your healthcare provider.

Sodium: sources

den Elzen WPJ, Brouwer N, Thelen MH, Le Cessie S, Haagen I-A, Cobbaert CM. NUMBER: standardized reference intervals in the Netherlands using a 'big data' approach. Clin Chem Lab Med 2018;57(1):42-56. (retrieved 2026) doi.org

Tests with related values

These panels measure values from the same category as this marker.

Iron test

Ferritin and haemoglobin: iron stores and anaemia in one test.

Ferritin Hemoglobin

€71,-

Full blood test

Twenty values from one draw: liver, kidneys, lipids, glucose, blood count, thyroid, iron and inflammation.

ALT (Alanine Aminotransferase) AST (Aspartate Aminotransferase) ALP (Alkaline Phosphatase) GGT (Gamma-Glutamyl Transferase) Creatinine eGFR (Estimated Glomerular Filtration Rate) Total Cholesterol HDL Cholesterol LDL Cholesterol Triglycerides Glucose (Fasting) Hemoglobin Hematocrit Erythrocytes (RBC) Leukocytes (WBC) MCV (Mean Corpuscular Volume) Platelets (Thrombocytes) TSH (Thyroid Stimulating Hormone) Ferritin CRP (C-Reactive Protein)

€199,-

Results without a doctor's assessment

You receive your values with the unit and reference range. A doctor's assessment is not part of this site. Discuss your results with your GP for explanation and treatment decisions.

Sodium

€7,-