Can this result diagnose a condition on its own?

No. Laboratory results are interpreted with symptoms, medical history, specimen conditions and related tests.

Which reference range should I use?

Start with the performing laboratory's own reference interval; clinical cutoffs, when relevant, are separate sourced thresholds used for a specific purpose.

When should I discuss the result with a healthcare professional?

Results that are clearly outside range, persistent, symptomatic or unexpected should be reviewed by a healthcare professional.

Information about a laboratory test

Sodium: What Does This Test Measure?

Measures the concentration of sodium, the major extracellular electrolyte, in blood.

Test summary

Test name: Sodium
Abbreviations: Na, Na+
Category: Electrolytes / Fluid Balance
Panel: Electrolyte Panel / Basic Metabolic Panel
Specimen: Serum / plasma
Common units: mEq/L, mmol/L

What does the test measure?

Measures the concentration of sodium, the major extracellular electrolyte, in blood.

Why is the test ordered?

Used as part of an electrolyte panel to assess fluid balance, kidney function and selected hormonal or neurologic conditions.

Information about a low result

Low sodium can occur with excess body water, certain fluid losses/replacement patterns, medicines, heart/kidney/liver conditions or hormonal disorders.

Information about a high result

High sodium is often related to water deficit or impaired access/balance of water, though other causes are possible.

Reference and clinical context

Start with the performing laboratory's reference interval, unit and specimen conditions. Numeric information on this page is stored as sourced example intervals or clinical thresholds.

Reference range 1

>= 135 – <= 145 mmol/L

Population: Adults
Age range: 18
Specimen: Serum / plasma

Example adult Sodium reference interval

The source presents these values as a common example reference interval. Laboratory method, age and clinical context can change the range; the user's own report takes priority.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

Sodium is interpreted with other electrolytes, glucose, kidney function and fluid status. Marked abnormalities can be clinically urgent.

Related specialties

Internal Medicine
Nephrology
Emergency Medicine
Endocrinology

Frequently asked questions

More information about this test

Sources

Comprehensive Metabolic Panel — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Example adult intervals for ALT, AST, ALP, albumin, bilirubin, total protein, BUN, creatinine and electrolytes · Verified: Aug 12, 2026
Creatinine Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Creatinine limitations and use with eGFR, BUN and urine testing · Verified: Aug 12, 2026
Electrolyte Panel — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Sodium, potassium, chloride and bicarbonate as an electrolyte panel · Verified: Aug 12, 2026
Sodium Blood Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Sodium interpretation with fluid balance and other electrolytes · Verified: Aug 12, 2026
Chloride Blood Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Chloride interpretation with sodium and acid-base balance · Verified: Aug 12, 2026
Carbon Dioxide (CO2) in Blood — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Serum total CO2/bicarbonate and acid-base context · Verified: Aug 12, 2026