Magnesium, Urine Test
Magnesium, Urine Test is a laboratory test you can order directly. A magnesium, urine test measures how much magnesium is leaving your body in urine. It is usually ordered to check for low or high magnesium levels, to look for kidney-related losses, or to monitor a condition that affects magnesium balance.
- Sample type
- urine
- Category
- Vitamin & Mineral
- Turnaround
- 1-3 business days
- Price
- $152
- Referral
- Not required
A magnesium, urine test measures how much magnesium is leaving your body in urine. It is usually ordered to check for low or high magnesium levels, to look for kidney-related losses, or to monitor a condition that affects magnesium balance.
What it measures
- Urine magnesium — The amount of magnesium in the urine sample.
- 24-hour urine volume — Total urine collected over the full test period, used to calculate total magnesium output.
- Creatinine — A waste product used to help confirm the collection is complete and to compare magnesium to kidney function.
- Collection duration — The exact number of hours the urine was collected, which affects how results are interpreted.
Who it is for
This test is typically ordered by a clinician when magnesium levels need to be checked, such as in people with kidney problems, digestive conditions, or symptoms that may relate to mineral imbalance. It may also be used to monitor treatment or a known magnesium disorder.
Preparation
Preparation depends on the collection type. A 24-hour urine test usually requires collecting all urine over a full day, often with a specific start and stop time; a random sample needs no special preparation. Follow the instructions given by your clinician or lab.
Results and what they mean
Results are reported as the amount of magnesium in the urine, often as a total over 24 hours or as a concentration. Your clinician compares the result with the collection details and your health history to interpret it. This is general information only and is not medical advice; only a qualified clinician can interpret your results.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the magnesium, urine test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for this test?
Fasting is usually not required for a urine magnesium test. Follow any specific instructions from your clinician or lab.
What if I miss part of my 24-hour collection?
Tell the lab or your clinician. An incomplete collection can make the result hard to interpret, and the test may need to be repeated.
Can I take my usual medicines?
Ask your clinician before the test. Some medicines and supplements can affect magnesium levels, so you may need to adjust them.
How long does it take to get results?
Results are typically available in 1 to 3 business days after the sample reaches the lab.