Exhaled Carbon Monoxide Concentration Less than or Equal to 4 ppm

**Semantic type:** Laboratory or Test Result

**Definition:** An indication that the concentration of carbon monoxide (CO) in a sample of exhaled air is less than or equal to 4 ppm.

**Synonyms:** - Exhaled CO Less than or Equal to 4 ppm - Exhaled CO Level <= 4 ppm - Exhaled Carbon Monoxide Less than or Equal to 4 ppm - Exhaled Carbon Monoxide Level Less than or Equal to 4 ppm