What does the Arsenic, Blood test measure?

Why is Arsenic, Blood measured?

Blood arsenic is used to confirm acute or very recent inorganic arsenic exposure in symptomatic patients or shortly after a known exposure event. Because arsenic clears rapidly from blood into tissue and urine, an elevated level documents recent intake but a normal value does not exclude past exposure or chronic low-level poisoning. For chronic or occupational surveillance, urine arsenic with speciation is the preferred matrix. Seafood consumption within the preceding 48 hours can elevate total blood arsenic substantially, so timing and dietary history are critical to interpretation.

Reference ranges

Standard reference

Background typically <7 µg/L; interpretation requires speciation to distinguish inorganic (toxic) from organic arsenicals.

Functional medicine optimal

Whole-blood arsenic <3–5 µg/L in individuals with no occupational exposure and no recent seafood intake; however, clinical decisions are based on the speciated inorganic fraction when possible and the exposure context.

Units

µg/L, µg/dL, nmol/L

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