Sequential combination of self-report, breath carbon monoxide, and saliva cotinine to assess smoking status.

The purpose of this analysis was to develop an algorithm for the cost effective and accurate assessment of smoking during the previous few days by combining self-report, breath carbon monoxide (BCO), and saliva cotinine (sCOT). These measurements are convenient, quantitative, and do not require invasive procedures. The data used to devise the algorithm were gathered during a treatment trial of participants seeking to stop smoking. Self-report of smoking was determined using a written questionnaire, BCO was measured with a handheld breathalyzer, and sCOT was quantified using a high sensitivity ELISA. Participants were 130 males and 97 females between the ages of 19 and 67 years who reported smoking at least 15 cigarettes a day and had a BCO level ≥ 15 ppm. Self-reports and BCO levels were collected at each of 6 visits (V0-V5) and sCOT levels were determined at V0 and V5. Based on the data collected, we recommend that the sequential determination of self-reported smoking, BCO level, and sCOT level be employed to assess smoking during the previous few days to minimize the higher cost and longer turnaround time associated with the sCOT test while maximizing accuracy.