How Does Methanol Affect Breathalyzer Readings?

[Moe*]

If a person drank methanol, they would go blind, and their breathalyser analysis (in units of mg/100 mL blood) would be in error. Its reading would be?

 

[chemisttree]

I believe that the breathalyzer uses an oxidation reaction (potassium dichromate, silver nitrate, sulfuric acid) to convert the dichromate into chromate which is then measured. All things being equal, the error should be on the order of the ratio of the molecular weight of ethanol to methanol and the results expressed in mg/l. The reading would be high by that ratio.