Arsenic Speciation, Random, Urine

Casandra

Casandra Test Code MC36413Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID SPASCPT Code 82175

Arsenic Speciation, Random, Urine

Clinical Use

Use

This test is useful for diagnosing arsenic intoxication using random urine specimens. It first measures total arsenic; if that concentration is ≥ 10 µg/L, speciation into inorganic, methylated, and organic forms is performed to distinguish between toxic and non‑toxic arsenic species. Elevated organic arsenic typically reflects dietary exposure (e.g., from seafood), whereas inorganic arsenic reflects toxic exposure. The analytical turnaround time is up to 3 to 5 days. Specimen stability, algorithm, and analytic details support accurate clinical interpretation.

Special Instructions

Testing algorithm: Total arsenic performed first; speciation follows only if total arsenic ≥ 10 µg/L; otherwise result reported as “< 10 µg/L” and no speciation. Patient prep: avoid seafood for at least 48 h prior to collection; delay collection for 96 h if gadolinium‑ or iodine‑based contrast media have been administered. Supplies include 10 mL urine tubes (T068) and 5 mL Sarstedt aliquot tube (T914). Use clean, plastic containers with no metal cap or glued insert. Refer to “Metals Analysis Specimen Collection and Transport” instructions. Refrigerated transport preferred; ambient or frozen acceptable per stability guidelines.

Limitations

Seafood ingestion may elevate non‑toxic (organic) arsenic and confound interpretation. High gadolinium or iodine contrast loads can interfere with ICP‑MS metal testing. Interpretation depends on timing of exposure versus half‑lives of different arsenic species. Total arsenic below 10 µg/L precludes speciation, possibly missing low‑level toxic exposures.

Test Details

New York Approved