Oxygen saturation - decreased, should improve with removal from exposure
No definitive test for<unk> 
Consider other diagnostic testing to rule out other causes if unsure exposure or lack of improvement:
EKG
CXR
Head CT
ABG
Carboxyhemoglobin
EKG
CXR
Head CT
ABG
Carboxyhemoglobin
Clinical/diagnosis of exclusion
Often based on history of exposure
Often based on history of exposure
Methane toxicity
Methemoglobinemia
Chloroform toxicity
Altitude related illness
Hydrocarbon toxicity
Primary CNS disease
Organophosphate toxicity
ACS