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Blood Test Tracker

Mercury, Urine

Mercury in a single urine sample, mostly from inorganic or elemental mercury such as vapor from spills, fillings or work exposure.

AI-drafted. Awaiting verificationLOINC 5689-5

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What it is

This test measures mercury in a random (spot) urine sample, reported in micrograms per liter. Urine mostly reflects inorganic and elemental mercury, the forms in vapor from spills, some industrial work and, in small amounts, dental amalgam fillings. Mercury from fish, called methylmercury, is better measured in blood. A spot sample can be watery or concentrated, so many labs also report mercury per gram of creatinine, which is a separate marker.

Why it matters

Ongoing contact with elemental or inorganic mercury can affect the nervous system and the kidneys. A urine test is one way to look at that kind of exposure, and ARUP Laboratories prefers it for long-term (chronic) exposure. For recent exposure, and for mercury from fish, a blood test is the better choice.

If it’s high

A higher result means more mercury is leaving your body than is typical. That can be a sign of contact with inorganic or elemental mercury. A contaminated sample can also give an unexpected result, so a repeat test is sometimes reasonable. How a given level affects a person varies a lot.

Common causes

  • A sample contaminated by skin, dust or a container that was not trace-element-free
  • Dental amalgam (silver) fillings, which usually add only a small amount
  • Work that involves mercury, such as dentistry, gold mining or some manufacturing
  • Broken thermometers, gauges or other liquid mercury spills
  • Some skin-lightening creams and traditional remedies that contain mercury
  • A sample collected after a chelating medicine

What can help

  • Ask your clinician whether the result fits your history, and whether to repeat it in a certified trace-element-free container
  • If you work with mercury, ask about workplace exposure monitoring and protective equipment
  • Follow local public-health guidance for cleaning up liquid mercury spills
  • Check skin-lightening creams and traditional remedies for mercury on the label
  • Ask whether a blood mercury test would add information, especially if you eat a lot of fish

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: up to 5 µg/L. Source: ARUP Laboratories.

What can affect your result

  • How dilute or concentrated your urine is
  • Seafood in the days before collection
  • Recent contrast dye (gadolinium or iodine)
  • The number of dental amalgam fillings
  • Work, hobby or home exposure to mercury
  • The collection container and how the sample was kept
  • Seafood in the 2 to 3 days before collection. ARUP asks you to avoid shellfish and seafood for 48 to 72 hours.
  • Gadolinium or iodine contrast dye can interfere with this kind of metal test. Mayo Clinic Laboratories asks for a 96-hour wait after contrast, and ARUP asks for at least 72 hours (14 days if kidney function is reduced).
  • A sample contaminated by skin, dust or a container that is not certified trace-element-free can read falsely high. Labs may ask for a repeat in a certified container.
  • Urine collected after a chelating (metal-binding) medicine, called a provoked or challenge test, has no valid reference range.
  • A random (spot) urine sample can be more dilute or more concentrated, which is why many labs also report mercury per gram of creatinine.
  • ARUP lists diet, supplements, vitamins and minerals as possible sources of interference. Ask your clinician before stopping anything.

Weeks to months. Inorganic mercury leaves the body slowly.

When to talk to a clinician

Talk with your clinician soon if your result is above your lab's range, especially if you work with mercury or have a tremor, unusual irritability, memory or sleep trouble, heavy drooling or gum problems. If you may have breathed vapor from a large mercury spill and feel unwell, seek urgent care.

Questions you could ask

  • Is a spot urine, a 24-hour urine or a blood test the best fit for my situation?
  • Could my job, hobbies or home be a source of mercury?
  • Should we repeat the test in a certified trace-element-free container?
  • Would a blood mercury test or a creatinine-corrected result add anything?

Questions people ask

Why do I have both a µg/L and a µg/g creatinine result?

The µg/L number is the raw concentration in your sample. The µg/g creatinine number adjusts for how watery or concentrated the sample was. The adjusted number is often easier to compare from one test to the next.

Does eating fish raise urine mercury?

Fish mercury (methylmercury) mostly shows up in blood, and urine mostly reflects inorganic and elemental mercury. Labs still usually ask you to avoid seafood for a couple of days before collection, so follow your lab's instructions.

What is a provoked urine mercury test?

It is a urine test collected after taking a chelating medicine. Normal ranges don't apply to those samples, and the American College of Medical Toxicology recommends against using them. Talk with your clinician if one was suggested to you.

Show the science and sources

Units

  • 1 µg/L = 1 µg/L
  • 1 µg/L = 4.985 nmol/L

Open the Urine Mercury unit converter

For clinicians and researchers

Random urine by ICP-MS (ARUP 2011481 reports µg/L together with a µg/g creatinine value). ARUP states that urine mercury predominantly reflects acute or chronic elemental or inorganic mercury exposure, that unexposed people are typically below 10 µg/L, that 24-hour concentrations of 30 to 100 µg/L may be associated with subclinical neuropsychiatric symptoms and tremor, and that above 100 µg/L can accompany overt neuropsychiatric disturbance. ARUP also warns that elevated results may reflect skin or collection contamination and recommends confirming with a second specimen in a certified trace-element-free container. The Mayo Clinic Laboratories random-urine test (HGUCR) reports the creatinine-corrected ratio (below 2 µg/g in adults), and no Mayo µg/L interval was found. Post-chelator challenge urine has no valid reference range, and the American College of Medical Toxicology recommends against that testing. Spot concentrations depend on urine dilution, so creatinine correction or a 24-hour collection is often used for interpretation.

LOINC 5689-5 (primary), 30921-1, 34338-4. Specimen: urine.

Sources

  1. Mercury, Random Urine (test 2011481), ARUP Laboratories
  2. Mercury/Creatinine Ratio, Random, Urine (test HGUCR), Mayo Clinic Laboratories (via the testcatalog.org mirror)
  3. ACMT Recommends Against Use of Post-Chelator Challenge Urinary Metal Testing, American College of Medical Toxicology (Journal of Medical Toxicology) (2017)
  4. Mercury (compound summary), PubChem, National Library of Medicine

AI-drafted. Awaiting verification. Last reviewed 2026-10-03. How we build and check these pages.

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