The Minnesota Department of Health (MDH) recommends urine mercury testing to assess whether an individual has an elevated exposure to forms of mercury found in skin lightening products.

Total urinary mercury mostly reflects elemental and inorganic mercury exposure. Inorganic mercury is an ingredient used in skin lightening and other beauty products. Elemental mercury is found in compact fluorescent lightbulbs and mercury thermometers and other devices.

In contrast, total blood mercury mostly reflects dietary intake of organic mercury.

What are the types of urine mercury tests?

Spot Urine Test: To best assess inorganic/elemental mercury, MDH recommends a spot urine test with a preservative. This test is a one-time urine screen.

24-hour Urine Mercury Test: This test requires urine collection for a period of 24 hours. It may underestimate total inorganic/elemental mercury exposure if the mercury vaporizes during the period of time the urine is being collected.

How are the results interpreted?

MDH has developed the following guidelines in consultation with the Minnesota Poison Control.

In the general population, normal urine mercury levels should be 5 mcg/L or less. At levels greater than 5 mcg/L, symptoms may be present, and an elevated exposure is likely occurring, which should be assessed through a home visit. At levels greater than 100 mcg/L, acute health effects are possible, and a toxicologist should be consulted as soon as possible through Minnesota Poison Control.

Quantity	Description
<5 mcg/L	Typical urine levels.
>=5 mcg/L	Symptoms of mercury exposure are possible, and a home visit should be offered for source control.
>=100mcg/L	Acute health effects are possible, and a toxicologist should be consulted as soon as possible.

What is the home visit process?

If a patient has urine mercury levels >= 5 mcg/L, MDH can help facilitate a home visit, with the agreement of the patient. The goal of the home visit is to identify and control the source of mercury exposure. The home visit team includes toxicology or public health staff, technical staff from the Minnesota Pollution Control Agency to perform air testing for mercury, and an interpreter if needed.

During the visit, sources of mercury exposure, ways to reduce them, and possible health effects and symptoms will be discussed with the patient. Using a hand-held mercury air analyzer, products in the home and air levels in different parts of the home will be tested for mercury contamination. If contaminated products are found, staff will offer to safely dispose of them.

Additional home visits may be needed to be sure air levels decrease and to check for additional products.

Re-test recommendation

To determine whether source control was effective a urine re-test after 60 days should be ordered. Urine mercury levels should be decreasing by at least 50% after 60 days.

Additional resources

Health information for the general public

Skin lightening products tested:
Skin Lightening Products Found to Contain Mercury, Hydroquinone and/or Steroids(PDF)

For questions about urine mercury tests contact MDH by phone 651-201-4899 or email Health.Biomonitoring@state.mn.us.

For consultations about clinical management of acute exposures, in particular acute symptomatic exposures, contact Minnesota Poison Control Center at 800-222-1222.