Michigan 2014 CO Surveillance report (publ 2016).pdf (1.03 MB)

   This review that Martha Stanbury co-authored found 50% of non-smokers and 51% of smokers who were confirmed as non-occupational cases of CO poisoning by investigation had COHb% below 5% or 10%, respectively (Table 8).  
    The prevalence of low COHb levels among confirmed occupational cases was even higher, with 64% of non-smokers under 5% and 59% of smokers under 10%.   
     These results cast doubt on the appropriateness of using COHb thresholds to confirm cases, unless also specifying that lower COHb levels are not grounds for excluding cases who may meet alternative criteria (such as 1 or more CO symptoms and a recent CO exposure confirmed by some alarm or inspection).   
     -- Albert Donnay