--- title: Magnesium Test type: biomarker url: "https://www.test-well.com/biomarkers/magnesium" also_known_as: - magnesium - mg category: Metabolic Health units: - mg/dL order_price_usd: 19.99 order_item: Magnesium order_url: "https://www.test-well.com/tests/magnesium" reviewed_at: 2026-09-06 --- # Magnesium > Magnesium is measured with a standard blood draw; no fasting is needed. A typical reference range is 1.70 – 2.20 mg/dL. At TestWell it's $19.99 all-in as Magnesium, results in 2–4 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis. Also known as: magnesium, mg. ## Key facts | Fact | Value | | --- | --- | | Units | mg/dL | | Sample | Blood draw | | Fasting | Not required | | Results | 2–4 business days | | Price | $19.99 | | Labs | Quest or Labcorp · BioReference in NY/NJ | ## What does Magnesium measure? A mineral involved in 300+ enzyme reactions, including muscle, nerve, and heart function. ## What is the normal range for Magnesium? | Population | Reference range | | --- | --- | | age 18+ | 1.70 – 2.20 mg/dL | Reference intervals differ slightly between labs; the range printed on your report is the one to interpret against. Ranges are usually set so 95% of healthy people fall inside them. ## What does a high Magnesium mean? High magnesium (hypermagnesemia) is uncommon in people with normal kidneys. It's usually from magnesium-containing laxatives, antacids or supplements in someone with reduced kidney function, or from IV magnesium in a medical setting. Mild elevations cause few symptoms; higher levels cause weakness, low blood pressure and slowed heart rhythm. ### Common causes of high Magnesium 1. Magnesium laxatives, antacids or high-dose supplements with reduced kidney function 2. Chronic kidney disease 3. Hypothyroidism, adrenal insufficiency, lithium (mild) 4. Sample hemolysis (mild artifact) ### Symptoms that go with high Magnesium - Nausea, flushing, weakness - Low blood pressure, slow heartbeat, drowsiness when high ### What clinicians usually check next - Kidney function - Stop magnesium-containing products - Repeat **Can magnesium supplements cause a high level?** In healthy kidneys, rarely — excess is excreted. With reduced kidney function, yes, which is why supplements need care in kidney disease. ## What does a low Magnesium mean? Low magnesium is common and often missed: proton-pump inhibitors, diuretics, alcohol, diarrhea, poorly controlled diabetes and low intake are the usual causes. Because most magnesium is inside cells, a normal serum level doesn't exclude deficiency, but a low one confirms it. Low magnesium drags potassium and calcium down with it and causes cramps, palpitations and fatigue. ### Common causes of low Magnesium 1. Proton-pump inhibitors (long-term), diuretics, some antibiotics and chemotherapy 2. Alcohol use disorder 3. Chronic diarrhea, malabsorption, bariatric surgery 4. Poorly controlled diabetes (urinary loss) 5. Low dietary intake ### Symptoms that go with low Magnesium - Muscle cramps, twitches, weakness - Palpitations - Fatigue, poor sleep - Numbness, tremor when more severe ### What clinicians usually check next - Potassium and calcium (often low together) - Medication and alcohol review - Kidney function - Repeat after correcting the cause Follow-up tests at TestWell: [Calcium](https://www.test-well.com/tests/calcium) ($26.99). ### Seek care promptly if - Low magnesium with palpitations, an irregular pulse or seizures — same-day care **Can my magnesium be low even if the blood test is normal?** Yes — serum magnesium is about 1% of the body's total. A low result is meaningful; a normal one doesn't rule deficiency out when symptoms and risk factors fit. ## How do you get tested for Magnesium? | Order | Type | Price | Includes | | --- | --- | --- | --- | | [Magnesium](https://www.test-well.com/tests/magnesium) | Single test | $19.99 | This marker | | [Fitness & Performance Panel](https://www.test-well.com/tests/fitness-performance-panel) | Panel | $119.99 | 8 tests | | [Sleep Health Panel](https://www.test-well.com/tests/sleep-health-panel) | Panel | $129.99 | 8 tests | | [Vitamin & Mineral Deficiency Panel](https://www.test-well.com/tests/vitamin-mineral-panel) | Panel | $189.99 | 9 tests | | [Total Body Panel](https://www.test-well.com/tests/total-body-panel) | Panel | $499.99 | 49 tests | ## Quest vs Labcorp vs BioReference | Lab | Available | Price | Notes | | --- | --- | --- | --- | | Quest Diagnostics | Yes | $19.99 | Choose Quest at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. | | Labcorp | Yes | $19.99 | Choose Labcorp at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. | | BioReference (NY & NJ) | Yes | $20.99 | New York and New Jersey orders route here automatically — state rules keep Quest and Labcorp from accepting self-ordered draws. | ## Common questions about Magnesium ### Do I need a doctor's order to test my magnesium? No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor. ### How long does it take to get Magnesium results? Most Magnesium results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal. ### How much does a Magnesium test cost? Our Magnesium starts at $19.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted. ### Do I need to fast before my Magnesium test? Fasting is not required for the Magnesium test. You can have your blood drawn any time of day. ### Which lab will process my Magnesium test? Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations. ## Sources - [Mayo Clinic Labs](https://www.mayocliniclabs.com/test-catalog/overview/8448) - [MedlinePlus (NIH) — Magnesium Blood Test](https://medlineplus.gov/lab-tests/magnesium-blood-test/) ## Related biomarkers - [Glucose](https://www.test-well.com/biomarkers/glucose) - [Creatinine](https://www.test-well.com/biomarkers/creatinine) - [eGFR](https://www.test-well.com/biomarkers/egfr) - [BUN](https://www.test-well.com/biomarkers/bun) - [ALT](https://www.test-well.com/biomarkers/alt) - [AST](https://www.test-well.com/biomarkers/ast) - [Reference range lookup tool](https://www.test-well.com/tools/reference-range-lookup) - [Lab unit converter](https://www.test-well.com/tools/lab-unit-converter) - [All biomarkers](https://www.test-well.com/biomarkers) --- Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-06. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md Canonical page: https://www.test-well.com/biomarkers/magnesium Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.