Mercury, Blood
The amount of mercury in the blood, mainly reflecting recent fish consumption.
| Typical reference range | below 10 ug/L |
| Commonly cited optimal range | below 5 ug/L |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Mercury is a toxic metal. Blood mercury mostly reflects methylmercury from fish and seafood eaten in the past few weeks to months; inorganic and elemental mercury exposures (dental amalgams, occupational sources, some skin-lightening creams) are better assessed by urine testing.
Why it matters
High mercury can damage the nervous system and kidneys and is of particular concern in pregnancy because it impairs fetal brain development.
What a high result can mean
Elevated levels most commonly reflect frequent consumption of high-mercury fish such as swordfish, shark, king mackerel, bigeye tuna and tilefish. Occupational exposure and certain imported cosmetics or traditional remedies are other sources.
What a low result can mean
Low levels are the goal and indicate limited exposure.
What affects the result
Reflects intake over roughly the past 1-3 months (half-life about 50 days). Switching to low-mercury seafood (salmon, sardines, shrimp, anchovies) lowers it. Avoid seafood for several days before testing only if a non-dietary baseline is specifically needed.
Units and conversion
Usually reported in ug/L.
- From ng/mL: multiply by 1 to get ug/L
- From nmol/L: multiply by 0.201 to get ug/L
- From ug/dL: multiply by 10 to get ug/L
Also called on lab reports
Mercury, Blood Mercury, Hg, Mercury, Whole Blood
Related tests: Toxins & Other
This page is educational and does not replace advice from a healthcare professional.