Study author Dr. Sridhar P. Reddy of St. Clair Pulmonary and Critical Care (OTCBB:CTCC), St. Clair, Mich., said that if smokers knew their blood carbon monoxide levels, they might be more motivated to quit smoking or never start in the first place.

The study originated as a high school science project by Reddy's son, Ashray Reddy, a sophomore at Detroit Country Day School. The doctor measured patients' carboxyhemoglobin, blood poisoned by carbon monoxide, and methhemoglobin, blood transformed by other substances, such as nitrogen dioxide, with a pulse cooximeter. The son developed and distributed questionnaires regarding the patients' smoking status.

A total of 476 patients participated and patients were identified as a smoker based on a combination of their questionnaire responses and if their carbon monoxide levels exceeded 6 percent of their blood. The study identified 98 patients as smokers, 72 were exposed to secondhand smoke and 306 were non-smokers.

The findings were presented at Chest 2007, the 73rd annual international scientific assembly of the American College of Chest Physicians in Chicago.