What does the Arsenic (Urine) test measure?

Why is Arsenic (Urine) measured?

Inorganic arsenic is a Group 1 IARC carcinogen causally associated with bladder, lung, and skin cancers following chronic exposure. Urinary total arsenic without speciation is clinically misleading in patients with regular fish or seafood consumption. Practitioners ordering this panel in patients with high seafood intake should request inorganic arsenic speciation, advise abstinence from seafood for 48–72 hours prior to collection, or interpret total arsenic with explicit acknowledgement of the dietary arsenic contribution. In functional medicine, arsenic is assessed alongside other toxic metals in patients with unexplained fatigue, peripheral neuropathy, skin changes, or those with identified high-exposure sources (contaminated well water, rice-heavy diets).

Reference ranges

Standard reference

<35 µg/g creatinine # REVIEWER FLAG: Total urinary arsenic is significantly elevated by organic arsenobetaine from seafood consumption — this is non-toxic but substantially inflates total arsenic. Confirm whether Mosaic Diagnostics reports total arsenic, inorganic arsenic fractionation (arsenite, arsenate, MMA, DMA), or both. Inorganic arsenic reference range is substantially lower (typically <10 µg/g creatinine). The clinical distinction between total and inorganic arsenic is critical for result interpretation.

Functional medicine optimal

Inorganic arsenic: <5 µg/g creatinine (functional medicine target following seafood abstinence). # REVIEWER FLAG: Confirm whether Mosaic Diagnostics provides inorganic fractionation or total only — interpretation guidance must specify accordingly.

Units

µg/g creatinine, µg/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.