Magnesium, RBC
Magnesium stored inside red blood cells, a more stable read on body magnesium than serum.
Consider this test if:
- Muscle cramps, twitching, palpitations, poor sleep, or persistent fatigue with no clear cause
- A normal serum magnesium but ongoing symptoms that suggest depletion
- Long-term use of diuretics, proton-pump inhibitors, or heavy alcohol intake
- Checking whether magnesium supplementation is actually restoring your stores
- HSA/FSA eligible
- Typical results in 2-4 days · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required. If you take magnesium supplements, note the dose and timing, since recent intake can raise the result; keep your routine consistent when comparing results over time.
Video consult with your Care Team
A 1:1 call to discuss your health.
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What this test is for
RBC magnesium measures the magnesium held inside red blood cells, which reflects your longer-term magnesium status more reliably than a single serum reading. Magnesium drives hundreds of enzymatic reactions, including muscle and nerve function, heart rhythm, blood sugar regulation, and energy production. Low magnesium is linked to muscle cramps, twitching, fatigue, irritability, palpitations, poor sleep, and headaches, and is more common with heavy alcohol use, certain diuretics or proton-pump inhibitors, and poorly controlled diabetes. Because the body keeps blood magnesium in a tight range by pulling from tissue stores, serum magnesium can read normal while you are actually depleted, which is why this intracellular measure is useful when deficiency is suspected.
This is the red-blood-cell form; the separate serum or plasma magnesium test is the routine, faster screen and the right default for acute or general checks.
- Specimen
- Red blood cells
- Measures
- Mass concentration
What you'll learn
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Insights that connect the dots. A clinician reads your whole picture, not one result in isolation, connecting family history, past results, and lifestyle into clear next steps.
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Your personalized action plan. Nutrition, supplements, and training in one clinician-reviewed protocol, updated as your results change.
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Track your trends. Upload results from any lab and see each biomarker trend over time, so you know what is working.
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Never miss a recheck. Mito tells you what is worth retesting and when, then reminds you so nothing slips.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Typical results in 2-4 days
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
Mito Membership
$9 /mo
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Without membership
$0
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost, covering the lab and what it takes to run the service. It is never a profit on the test itself. Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9 per month, and any applicable lab order or draw fee is itemized before you pay.
Where do I get tested?
Choose an available partner lab at checkout. If your cart contains multiple blood tests, Mito helps consolidate the eligible tests at one lab when possible. At-home kits and scans follow the collection or appointment process shown on their product page.
Is this eligible for HSA/FSA?
Yes. Eligible tests can be paid for with an HSA or FSA card at checkout.
When will I get my results?
Your results appear in your Mito dashboard after the laboratory completes processing. A clinician then reviews them before your analysis and personalized action plan are finalized. Timing varies by test, and specialty assays and at-home kits may take longer.
Do I need a physician's order?
No. Mito provides the laboratory order when one is required, so you do not need to arrange a separate physician visit before purchasing.
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