Figure 1
From: Assessment of smoking status based on cotinine levels in nasal lavage fluid
Cotinine level is of indicator smoking status. The median cotinine concentration in the NLF of non-smokers was 0.65 ng/ml, of passive smokers 0.64 ng/ml and of active smokers 4.78 ng/ml. Cotinine levels were significantly higher in the NLF of smokers than of that of either non-smokers non-exposed (p < 0.001) or non-smokers ETS (p < 0.001). No significant difference in cotinine levels between the non-smoker and nonsmoker ETS groups.