Magnesium

ChemistryAlso known as: Mg, serumAlso known as: Mg, plasmammol/(4.h)

Measures magnesium excretion in serum or plasma to assess magnesium balance and kidney handling.

Normal Range
2 – 3 mmol/(4.h)
mmol/(4.h)
Abnormal Levels
Consult your provider
Specimen Type
Blood

Why This Biomarker Matters

Urinary magnesium helps diagnose magnesium deficiency and evaluate causes of muscle weakness, fatigue, and irregular heartbeat. This test guides supplementation and dietary adjustments.

Understanding Your Results

Normal Range

2 – 3 mmol/(4.h)

Overview

Magnesium is a mineral essential for muscle function, energy production, and nerve signaling. A 24-hour urine magnesium test measures how much magnesium your body excretes, helping assess magnesium status and kidney function. Low urinary magnesium may indicate deficiency or malabsorption, while high levels could suggest excessive losses or dietary overload. This test is useful for evaluating muscle weakness, irregular heartbeat, and metabolic concerns.

Related Health Conditions

Conditions where Magnesium is commonly tested

Hypokalemia

Related Health Goals

Optimize Electrolyte Balance

Treatments & Interventions

Therapies monitored using Magnesium

Potassium chloride

Potassium acetate

Monobasic potassium phosphate

Dibasic potassium phosphate

Potassium bicarbonate

Potassium phosphate

Potassium gluconate

Potassium bitartrate

Triamterene

Spironolactone

Potassium citrate

Amiloride

Amiloride hydrochloride

Potassium citrate monohydrate

Amiloride hydrochloride anhydrous

Technical Information (LOINC Codes)

Standardized laboratory codes for this biomarker

19123-9Primary
Magnesium [Mass/volume] in Serum or Plasma
mg/dL
24447-5
Magnesium [Mass/time] in 24 hour Urine
mg/(24.h)
26746-8
Magnesium [Mass/volume] in Red Blood Cells
mg/dL
19124-7
Magnesium [Mass/volume] in Urine
mg/dL
2597-3
Magnesium [Moles/volume] in Red Blood Cells
mmol/L
2601-3
Magnesium [Moles/volume] in Serum or Plasma
mmol/L
18369-9
Magnesium [Moles/time] in 4 hour Urine
mmol/(4.h)
17236-1
Magnesium [Moles/volume] in Stool
mmol/L
17235-3
Magnesium [Moles/volume] in Leukocytes
mmol/L
49007-8
Magnesium [Moles/volume] in Peritoneal dialysis fluid
mmol/L
16172-9
Magnesium [Mass/mass] in Hair
mg/g
18368-1
Magnesium [Moles/time] in 2 hour Urine
mmol/(2.h)
21377-7
Magnesium [Mass/volume] in Blood
mg/dL
10880-3
Magnesium [Mass/mass] in Stool
mg/g
2598-1
Magnesium [Moles/volume] in Urine
mmol/L
29911-5
Magnesium [Mass/volume] in Stool
mg/dL
29912-3
Magnesium [Mass/time] in Stool
29365-4
Magnesium [Mass/volume] in Body fluid
mg/dL
2599-9
Magnesium [Moles/time] in 24 hour Urine
mmol/(24.h)
32024-2
Magnesium [Mass/volume] in 24 hour Urine
mg/dL
32329-5
Magnesium [Moles/volume] in Specimen
mmol/L
23892-3
Magnesium [Moles/time] in 24 hour Stool
mmol/(24.h)
23891-5
Magnesium [Moles/volume] in 24 hour Stool
mmol/L
26708-8
Magnesium [Moles/mass] in Stool
meq/kg
20872-8
Magnesium [Mass/volume] in Ocular fluid
mg/dL
27122-1
Magnesium [Mass/mass] in Red Blood Cells
ug/g{Hb}
27210-4
Magnesium [Presence] in Blood
27255-9
Magnesium [Moles/mass] in 24 hour Stool
meq/kg
29364-7
Magnesium [Mass/volume] in Cerebral spinal fluid
mg/dL
17237-9
Magnesium [Moles/mass] in Hair
umol/g
30536-7
Magnesium [Mass/volume] in Total parental nutrition
mg/dL
30922-9
Magnesium [Mass/volume] in Urine collected for unspecified duration
mg/L
42616-3
Magnesium [Mass/volume] in Dialysis fluid
mg/dL
14824-7
Magnesium [Presence] in Stone
52911-5
Magnesium [Moles/mass] in Tissue
umol/g
54919-6
Magnesium [Mass/volume] in Semen
mg/dL
55938-5
Magnesium [Moles/volume] in Total parental nutrition
mmol/L
57367-5
Magnesium [Mass/volume] in 12 hour Urine
mg/dL
57368-3
Magnesium [Mass/time] in 12 hour Urine
mg/(12.h)
57998-7
Magnesium [Mass/volume] in Nonbiological fluid
mg/dL
58995-2
Magnesium [Mass/time] in 18 hour Urine
mg/(18.h)
74696-6
Magnesium [Moles/volume] in 12 hour Urine
umol/L
87469-3
Magnesium [Mass/volume] in Specimen
ug/dL
87470-1
Magnesium [Mass/mass] in Specimen
ug/g
94256-5
Magnesium [Mass/volume] in Sweat
mg/dL
2594-0
Magnesium [Moles/volume] in Cerebral spinal fluid
mmol/L
9478-9
Magnesium [Mass/volume] in Water
[ppm]
2595-7
Magnesium [Moles/volume] in Dialysis fluid
mmol/L
25954-9
Magnesium [Moles/volume] in 24 hour Urine
mmol/L
2596-5
Magnesium [Moles/volume] in Body fluid
mmol/L
2593-2
Magnesium [Moles/volume] in Blood
mmol/L

Available Lab Tests

Order tests that measure this biomarker

Adrenal Complete

$340.56

Magnesium 24 Hour Urine Test with Creatinine

$38.39

Magnesium (RBC)

$24.70
Results in 1-2 business days

Magnesium (Serum)

$17.77
Results in Same day to 1 business day

Find Specialists

Doctors who commonly order this test

Internal Medicine
Nephrology