Sodium

ChemistryAlso known as: NaAlso known as: Serum sodiumAlso known as: Plasma sodiummmol/L

Measures sodium concentration in blood serum or plasma, reflecting overall body fluid and electrolyte balance.

Normal Range
138 – 146
mmol/L
Abnormal Levels
< 135 mmol/L
> 146 mmol/L
Specimen Type
Blood

Why This Biomarker Matters

Sodium is fundamental to nerve signaling, muscle function, and maintaining blood pressure. Hyponatremia (low sodium) and hypernatremia (high sodium) are among the most common electrolyte disorders encountered in clinical practice.

Optimal Ranges

Clinician-defined 4-point reference thresholds (mmol/L)

Default Range

135
138
143
146
Low
135 mmol/L
Borderline Low
138 mmol/L
Optimal
143 mmol/L
Borderline High
146 mmol/L

Overview

Sodium (Na+) is an essential electrolyte measured primarily in blood serum or plasma. It plays a critical role in fluid balance, nerve impulse transmission, and muscle contraction. Serum sodium is one of the most commonly ordered laboratory tests, included in both the Basic and Comprehensive Metabolic Panels. Abnormal levels indicate conditions ranging from dehydration and kidney disease to hormonal imbalances. Sodium can also be measured in urine (to evaluate renal sodium handling) and stool (to differentiate causes of diarrhea).

Related Health Conditions

Conditions where Sodium is commonly tested

Bipolar disorder

Diabetes mellitus type II

Hyponatremia

Related Health Goals

Monitor Blood Sugar

Optimize Electrolyte Balance

Optimize Metabolic Function

Support Mental Wellness

Treatments & Interventions

Therapies monitored using Sodium

Valproate semisodium

Maprotiline hydrochloride

Methotrimeprazine hydrochloride

Lithium

Human insulin

Quetiapine fumarate

Tiagabine hydrochloride

Sodium acetate

Miglitol

Metformin hydrochloride

Tolbutamide sodium

Rosiglitazone maleate

Pioglitazone hydrochloride

Human insulin-containing product

Colesevelam hydrochloride

Clinical Trials

903
Total Trials
103
Recruiting
282
With Results

Recent Trials

Family Investigation of Nephropathy and Diabetes (F.I.N.D.)

NCT00342927Recruiting100,000 enrolled

A Study of Cardiovascular Events iN Diabetes Plus

NCT05441267Phase 4Recruiting20,000 enrolled

A Pragmatic Trial Comparing Empagliflozin and Dapagliflozin Through Cluster Randomization Embedded in the Electronic Health Record

NCT06642272Phase 4Recruiting17,200 enrolled

EASi-PROTKT™ - A Study to Test Vicadrostat (BI 690517) Taken Together With Empagliflozin in People With Type 2 Diabetes, High Blood Pressure, and Cardiovascular Disease

NCT07064473Phase 3Recruiting11,800 enrolled

Intervention for High-normal Blood Pressure in Adults With Type 2 Diabetes

NCT03264352Phase 4Recruiting11,414 enrolled
View all 903 trials on ClinicalTrials.gov

Technical Information (LOINC Codes)

Standardized laboratory codes for this biomarker

2951-2Primary
Sodium [Moles/volume] in Serum or Plasma
mmol/L
2956-1
Sodium [Moles/time] in 24 hour Urine
mmol/(24.h)
21525-1
Sodium [Moles/volume] in 24 hour Urine
mol/L
2947-0
Sodium [Moles/volume] in Blood
mmol/L
2955-3
Sodium [Moles/volume] in Urine
mmol/L
35678-2
Sodium [Moles/volume] in Urine collected for unspecified duration
mmol/L
27257-5
Sodium [Moles/mass] in 24 hour Stool
meq/kg
18377-2
Sodium [Moles/time] in 12 hour Urine
mmol/(12.h)
87451-1
Sodium [Mass/volume] in Specimen
mg/dL
27419-1
Sodium [Moles/time] in 24 hour Stool
mmol/(24.h)
39792-7
Sodium [Moles/volume] in Capillary blood
mmol/L
2948-8
Sodium [Moles/volume] in Cerebral spinal fluid
mmol/L
2952-0
Sodium [Molar amount] in 24 hour Stool
mmol
21527-7
Sodium [Mass/time] in 24 hour Urine
mg/(24.h)
21526-9
Sodium [Mass/volume] in 24 hour Urine
mg/dL
15207-4
Sodium [Moles/volume] in Stool
mmol/L
32340-2
Sodium [Moles/volume] in Specimen
mmol/L
2950-4
Sodium [Moles/volume] in Body fluid
mmol/L
41657-8
Sodium [Moles/volume] in Mixed venous blood
mmol/L
32717-1
Sodium [Moles/volume] in Arterial blood
mmol/L
39791-9
Sodium [Moles/volume] in Venous blood
mmol/L
57370-9
Sodium [Moles/volume] in 12 hour Urine
mmol/L
57382-4
Sodium [Moles/volume] in 2 hour Urine
mmol/L
58994-5
Sodium [Moles/time] in 18 hour Urine
mmol/(18.h)
59163-6
Sodium [Moles/volume] in 24 hour Stool
mmol/L
60220-1
Sodium [Moles/volume] in Mother's milk
mmol/L
74685-9
Sodium [Moles/volume] in 4 hour Urine
umol/L
77139-4
Sodium [Moles/volume] in Serum, Plasma or Blood
mmol/L
82812-9
Sodium [Mass/volume] in Red Blood Cells
mg/L
87452-9
Sodium [Mass/mass] in Specimen
ug/g
92572-7
Sodium [Molar amount] in 24 hour Dialysis fluid
mmol
94842-2
Sodium [Moles/volume] in Urine from Fetus
mmol/L
12907-2
Sodium [Moles/volume] in Red Blood Cells
mmol/L
9485-4
Sodium [Mass/volume] in Water
[ppm]
12908-0
Sodium [Moles/volume] in Vitreous fluid
mmol/L
13895-8
Sodium [Moles/volume] in Milk
mmol/L
14055-8
Sodium [Moles/mass] in Stool
mol/kg
17796-4
Sodium [Moles/volume] in Hyperal solution
mmol/L
18376-4
Sodium [Moles/time] in 6 hour Urine
mmol/(6.h)
26763-3
Sodium [Mass/time] in 2 hour Urine
mg/(2.h)
2949-6
Sodium [Moles/volume] in Dialysis fluid
mmol/L
2953-8
Sodium [Molar amount] in 72 hour Stool
mmol
2954-6
Sodium [Moles/volume] in Sweat
mmol/L
30558-1
Sodium [Moles/volume] in Total parental nutrition
mmol/L
32553-0
Sodium [Molar amount] in Urine collected for unspecified duration
mmol
39787-7
Sodium [Moles/volume] in Peritoneal dialysis fluid
mmol/L
44783-9
Sodium [Moles/volume] (Maximum value during study) in Serum or Plasma
mmol/L
49790-9
Sodium [Moles/volume] in Peritoneal fluid
mmol/L
49791-7
Sodium [Moles/volume] in Amniotic fluid
mmol/L
50911-7
Sodium [Moles/volume] in Gastric fluid
mmol/L
50912-5
Sodium [Moles/mass] in Hair
umol/g
51205-3
Sodium [Mass/mass] in Hair
ug/g
53122-8
Sodium [Moles/time] in 1 hour Urine
mmol/h
56979-8
Sodium [Moles/volume] in Saliva (oral fluid)
mmol/L

Available Lab Tests

Order tests that measure this biomarker

Adrenal Complete

$340.56

Advanced Cardiovascular Health Basic

$132.55

Advanced Cardiovascular Health Comprehensive

$526.57

Advanced Liver Health Basic

$293.92

Advanced Liver Health Comprehensive

$1044.34

Cancer Tumor Markers Men Basic

$71.57

Comprehensive Metabolic Panel (CMP)

$15.79
Results in Same day to 1 business day

Find Specialists

Doctors who commonly order this test

Family Medicine
Internal Medicine
Endocrinology, Diabetes & Metabolism
Nephrology
Psychiatry