Late confirmation of acute methyl bromide poisoning using S-methylcysteine adduct testing.

Methyl bromide poisoning is difficult to confirm because routine laboratory testing has not been reliable. Measurable levels of the parent agent are rapidly reduced, probably as a result of direct tissue chemical reaction. Serum bromide levels have been used as an indirect measure of exposure and/or toxicity but are inconsistent. Recently special testing has shown that protein adducts formed after exposure to methyl bromide may be a better measure of significant exposure. The S-methylcysteine adduct was used to confirm acute methyl bromide toxicity 10 weeks after an exposure. Additionally, genotyping of the glutathione-S-transferase TI enzyme in erthyrocytes from this case characterized a predisposition to the neurotoxic effects of methyl bromide.