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Magnesium, Red Blood Cell Content

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of magnesium naturally found inside red blood cells, which can help assess overall magnesium status or identify deficiencies.

Quick summary

["Red blood cell magnesium levels may indicate whether you have low magnesium or if it’s stored properly in your body’s cells."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
2597-3
Short code
Magnesium RBC-sCnc
Synonyms
Magnesium RBC-sCnc
Category
electrolyte
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
1.7
Ref high
2.2
Critical range
1 N/A – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83735
SNOMED
900000000000003001
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like muscle weakness, cramps, or irregular heartbeat, or if you’re at risk for magnesium deficiency (e.g., due to certain medical conditions, long-term use of certain medications, or poor diet). It may also be part of a broader evaluation for metabolic or electrolyte disorders.

What to Expect Before the Test

No special preparation is typically needed. You may have a simple blood draw from a vein in your arm, similar to other blood tests. If you’re on blood thinners or have a history of bleeding disorders, let your provider know before the test.

What the Results Mean

Results are compared to a general reference range for healthy adults, but individual results can vary based on factors like age, health status, and medications. Abnormal results may prompt further testing or evaluation of underlying causes.

Common Reasons for Abnormal Results

Low RBC magnesium could suggest a deficiency, while high levels might indicate conditions like kidney disease or certain metabolic disorders. Your provider will discuss these findings with you in detail.

Reference range

Adult: 1.7-2.2 mg/dLN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

RBC Magnesium

Frequently asked questions

What causes might lead to abnormal RBC magnesium levels?
RBC magnesium levels can be affected by dietary magnesium intake, kidney function, certain medications (like diuretics or antacids), chronic illnesses (e.g., diabetes or heart disease), or genetic factors. Abnormal results often prompt further investigation to identify the root cause.
How might my symptoms relate to RBC magnesium?
Symptoms like muscle spasms, fatigue, or irregular heartbeat may sometimes be linked to magnesium imbalances, but RBC magnesium alone isn’t always the direct cause. Your provider will consider your full medical picture when interpreting results.
Can I adjust my diet or take supplements based on this test?
If your results are low, your provider may recommend dietary changes (e.g., more nuts, seeds, or leafy greens) or supplements under medical supervision. Never self-treat without guidance, as magnesium can interact with other medications.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy