The short answer
Essential mineral for muscles, nerves, and sleep — up to 50% of Americans don't get enough, measured from a standard blood draw. At TestWell it costs $19.99 plus a $6 lab processing fee, needs no fasting, and results post in 2–4 business days. Physician-authorized with no doctor's visit or insurance needed; draw at Quest or Labcorp.
Hospital Lab
$80
cash pay
Other Labs
$25
+ lab fees
TestWell
$19.99
+ $6 lab processing fee
Magnesium is involved in over 300 enzymatic reactions in the body, including muscle and nerve function, blood sugar regulation, and blood pressure control. Despite its importance, an estimated 50% of Americans don't meet the recommended daily intake. Deficiency can cause muscle cramps, insomnia, anxiety, headaches, and irregular heartbeat.
Measures serum magnesium — a cofactor in 300+ enzymatic reactions including energy production, muscle contraction, sleep regulation, and blood-sugar control.
Anyone with muscle cramps, restless legs, insomnia, palpitations, migraine, or on medications that deplete magnesium (PPIs, diuretics, metformin). Increasingly ordered alongside Vitamin D for general wellness.
Sample Type
Blood draw
Fasting
Not required
Results In
2–4 business days
Performed At
Quest or Labcorp
Your Magnesium results will include values for each of the 1 biomarker tested, along with reference ranges. Results are reviewed by a licensed physician before being released to your secure portal.
If any values fall outside the normal range, your report will include guidance on what that may mean and recommended next steps. You'll receive an email notification when your results are ready, typically within 2–4 business days.
Typical reference range layout
Lab reports show where your value sits relative to established reference intervals—your physician interprets this in context for you. Already have results? Analyze them with your AI assistant against our physician-reviewed ranges.
No fasting required.
What can throw off this result
Physician-reviewed “Before your test” pages — what each factor does, for how long, and what to do about it.
A Magnesium test costs $19.99 at TestWell — $25.99 all-in when ordered alone, because the $6 lab processing fee is charged once per order, with no draw fee or physician fee added. Ordered directly from the labs' own consumer sites, the same test lists at $39.00 at Quest Health and $39.00 at Labcorp OnDemand (list prices checked Sep 12, 2026). Hospital outpatient labs typically bill around $80.00 self-pay for the same test, and often more. With insurance, what you pay depends on your deductible and your plan's negotiated rate; TestWell's price is fixed before the draw and is HSA/FSA-eligible. Full cost breakdown →
| Where you order | Price | One test, all-in | Notes |
|---|---|---|---|
| TestWell (drawn at Quest or Labcorp) | $19.99 | $25.99 | Includes the one $6 lab processing fee, charged once per order |
| TestWell (drawn at BioReference — New York & New Jersey) | $20.99 | $26.99 | New York and New Jersey orders route to BioReference; Quest Health and Labcorp OnDemand don't take self-ordered draws in those states |
| Quest Health (Quest Diagnostics' own site) | $39.00 | $39.00 | list price checked Sep 12, 2026 |
| Labcorp OnDemand (Labcorp's own site) | $39.00 | $39.00 | list price checked Sep 12, 2026 |
| Hospital outpatient lab, self-pay (typical) | $80.00 | $80.00 | Reference figure; hospital charges vary widely by facility and are often higher |
33% less than the lower lab-direct list price, for the same draw at the same lab. Lab test codes: Quest test code 622 · Labcorp test no. 001537 · BioReference code 0120-6. Competitor prices are read from the linked public pages and re-checked regularly; the labs' sites may add taxes or change prices without notice.
Compare more: Quest Diagnostics price list · Labcorp price list · Quest vs Labcorp · Lab test price checker
Serum magnesium is the standard and what most clinicians order. Only ~1% of body magnesium is in serum, so it can miss intracellular deficiency — but RBC magnesium isn't reliably validated outside research settings. Serum is the right call for routine testing.
TestWell charges $19.99 — vs $29 at Quest Direct and $50-$120 at hospital outpatient labs.
No fasting required. Avoid magnesium supplements for 24 hours before the draw for an accurate baseline.
Reference range: 1.7-2.2 mg/dL. Functional optimal: 2.0-2.2 mg/dL. <1.7 is overt deficiency; <2.0 is subclinical and often missed.
Ordered directly, a Magnesium test lists at $39.00 at Quest Health (Quest Diagnostics' own site) and $39.00 at Labcorp OnDemand (prices checked September 2026). TestWell orders the same test at the same Quest or Labcorp patient service centers for $19.99 — $25.99 all-in with the $6 per-order lab processing fee — paid out of pocket at checkout with no insurance, doctor's visit or draw fee; HSA and FSA cards are accepted.
Magnesium test results are typically ready in 2–4 business days after your draw at Quest or Labcorp. TestWell emails you the moment they post, and your results dashboard shows each marker against its reference range with a plain-English explanation.
Common medications and keto and high-protein diets can change a Magnesium test result without anything being wrong. Common medications can lower Magnesium — check magnesium and B12 on long-term PPIs. Keto and high-protein diets can lower Magnesium — hydrate and mention the diet if a metabolic panel is drawn in the transition. Each factor is covered on our physician-reviewed "Before your test" pages; when one applies, the fix is usually to remove it and retest.
Order the Magnesium test online from TestWell for $19.99 (plus a $6 per-order lab processing fee) — no doctor's visit, referral or insurance needed. A licensed physician authorizes the order, then you walk into any Quest or Labcorp patient service center near you for the draw (the lab locator on our site lists the closest ones by ZIP code), and results arrive in 2–4 business days.
The CPT code for a Magnesium test is 83735. You can order it from TestWell for $19.99 — no doctor's visit or insurance required, with results in 2–4 business days.
The Magnesium test is Quest Diagnostics test code 622, Labcorp test number 001537, BioReference code 0120-6 (CPT 83735). TestWell orders it under those codes for $19.99 at Quest, Labcorp or BioReference — no doctor's visit or insurance required, results in 2–4 business days. Codes verified against the labs' catalogs in 2026.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
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TestWell Price
$19.99
+ $6 lab processing fee at checkout
No insurance needed · HIPAA compliant
Better value: the Vitamin & Mineral Deficiency Panel
Save $106.92This test is part of the Vitamin & Mineral Deficiency Panel — 9 tests · 9 biomarkers for $189.99, $106.92 less than à la carte.
$189.99$296.91
9 tests · 9 biomarkers
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Magnesium
$19.99