HSA/FSA Eligible

About this test

What's tested
  • Magnesium, RBC via atomic absorption spectrometry (AAS); inductively-coupled plasma/mass spectrometry (ICP/MS)

This test measures magnesium levels inside red blood cells, providing a more accurate reflection of long-term magnesium status compared to standard serum tests. Since most of the body's magnesium is stored in cells, Magnesium, RBC offers a better gauge of overall sufficiency and how well magnesium is being utilized.

Why consider this test?

Magnesium is a critical regulator of neuromuscular function, cardiovascular stability, glucose metabolism, and cellular energy production. Despite its importance, deficiency is widespread and often underdiagnosed, as magnesium is not always included in routine blood work. Low levels have been linked to insulin resistance, arrhythmias, muscle dysfunction, and poor stress resilience. Measuring magnesium can help identify suboptimal status, guide targeted supplementation, and support both preventive health and peak physiologic performance.

Test details

  • Sample type: Blood

  • HSA/FSA: Accepted

  • Results: Emailed to you

  • Preparation: Fasted (8-12 hrs)

How it works

Purchase your tests

Purchase this test and any other tests you'd like online. A healthcare provider will review and approve your test requests; no healthcare provider visit is required.

Provide your sample

Visit a Labcorp location near you for sample collection. Use our Labcorp locator below to find a location near you.

Get your results

Our partnered facilities will process your bloodwork. Lab Results typically arrive within 14 business days, and we will email them to you as soon as they arrive.

Lab work FAQs

Please read our FAQs page to find out more.

How quickly will my lab results arrive?

Your lab results will typically arrive within two weeks, though processing time may vary based on the size and complexity of your panel. Rest assured, once your results are ready, they will be securely delivered to your email. No waiting rooms. No chasing paperwork. Just precision diagnostics at your fingertips.

Does Marek Diagnostics accept insurance?

Marek Diagnostics is a cash-pay service. Our platform offers direct access to comprehensive testing without the limitations, denials, or delays imposed by insurance companies. If traditional insurance covered the kind of proactive, high-quality lab work we offer, Marek Diagnostics wouldn’t need to exist. 

However, many clients successfully use their HSA/FSA to cover their testing costs. Marek Diagnostics is partnered with TrueMed for convenient deployment of HSA/FSA funds at checkout.

My panel Meets Treatment Requirements — what does that mean?

Marek Diagnostics is an extension of Marek Health, the leading health optimization platform designed to turn your results into informed action. 

If your panel Meets Treatment Requirements, you’re eligible to enroll into Guided Optimization, an exclusive program that connects you with:

  • Detailed, expert led lab analysis
  • A consultation with a Marek Health coach and board-certified medical provider
  • A precision health optimization plan
  • Access to high-quality treatment options

If you’re unsure what to do with your results, Marek Health is the bridge between lab results and achieving your goals.

Do I need to pay a separate fee at the lab to get my blood drawn?

No additional payment is required at the lab. Our expert-built panels include the venipuncture and if you’re building a custom panel or testing biomarkers individually, a $5 venipuncture fee will be automatically added at checkout. 

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