Heavy Metal Test Prep

Which sample to use, how a home urine test works, and what to avoid in the days before you collect it. Written in plain words, so your result reflects your body and not last night's dinner.

Choosing a sample

Blood, hair or urine?

The three tests answer different questions. Pick the one that fits what you want to know.

Blood

What's in you now

Shows recent exposure. Many metals don't stay long in the blood, so it can miss what has built up over years.

Hair

Picks up too much

Hair collects metals from outside too: shampoo, dye, smoke, dust. One hair sample sent to six labs came back with different answers, and no two labs flagged the same element as high.

Urine

What your body is clearing

For metals like cadmium and mercury, urine reflects the build-up over time. It can be collected at home.

At home

How a home urine test works

Get the kitHome urine kits are usually ordered through a doctor or practitioner, who also helps you read the result.
Prepare for two daysFollow the checklist below before you collect.
Collect your first urine of the morningUse the container in the kit and follow its instructions exactly. Some tests ask for a timed collection instead.
Keep it cold and send it soonRefrigerate the sample until you ship it. Send it early in the week, so it doesn't sit in a depot over the weekend.
Read the result with your doctorBring a list of your likely exposures: your job, hobbies, water, diet and home. A number means more alongside that list.

Before you collect

The prep checklist

Tick each one as you go. Your ticks stay on this device only.

48 hours beforeNo fish or shellfishSeafood can push up arsenic and mercury readings and make a normal result look high.

48 hours beforeAsk your doctor about pausing some supplementsVitamin C and any mineral the test measures (zinc, selenium, magnesium and similar) can change the reading. Don't stop anything without checking first.

96 hours beforeNo scans with contrast dyeMRI or CT contrast (gadolinium or iodine) can show up in urine. Wait four days after a contrast scan.

On the dayNot during your periodBlood in the sample can change the result. Collect on another day.

On the dayFirst urine of the morningCollect it straight into the kit's container, then refrigerate.

Any timeA plain test, with no drug taken firstSome tests give you a drug that pulls metals into the urine first. Almost anyone's levels rise after it, and the result is compared with people who took nothing. Medical toxicologists advise against using this to diagnose poisoning.

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Where this comes from

Sources

Seidel S. et al. Assessment of commercial laboratories performing hair mineral analysis. JAMA, 2001.
ATSDR (US Agency for Toxic Substances and Disease Registry). Cadmium: laboratory evaluation; Hair analysis panel.
Mayo Clinic Laboratories. Heavy metals screen, 24-hour urine: seafood avoidance and contrast-scan timing before a urine collection.
Laboratory collection instructions for urine element tests (seafood, supplements, menstruation, first-morning collection).
American College of Medical Toxicology. Position statement on post-chelator challenge urinary metal testing, 2010.

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