Salivary Cotinine Cutoff Value as a Mirror for Serum Cotinine in Chronic Smokers

Background: Cotinine is used most commonly as a marker to distinguish between tobacco smokers and non-smokers, it has greater sensitivity and specificity than other biochemical tests, Cotinine consider as a major metabolite of nicotine, can be easily detected in various body fluids like blood, saliva, urine. Objective: The target of this study was to evaluate cotinine concentration in saliva as a mirror for serum cotinine in chronic tobacco smokers, non-invasive, simple with no pain collection procedure when we need large samples are required over a limited period of time. Material and methods: Study design-One hundred male volunteers, were divided into two groups: the 1st group consisted of 58 smokers, each consumed 20 cigarettes/day for at least 10 years; and the 2nd group consisted of 48 non-smokers who were consider as a control group. The samples were taking from serum and un-stimulated saliva. Results: In this study showed a significant difference between control and smokers groups, (P>0.05), with cut-off (11.43 ng/mL) for saliva (sensitivity 96% and specificity of (85%) and (98.81) for serum with sensitivity (93%) and specificity of (88%). Conclusion: Many types of techniques have been used to measure cotinine like, gas chromatography, high performance liquid chromatography and colorimetric assays Immunoassays. Cotinine can be used widely in future compared to other diagnostic tools because of its higher sensitivity, specificity, long half-life. Moreover, it is the best indicator for distinguishing the tobacco smokers from non-smokers, saliva cotinine cut-offs in this study that can be used to distribute smokers and nonsmokers with impartially high sensitivity and specificity.