Introduction: Self-report and nicotine detection are methods to measure smoking exposure and can both lead to misclassification. It is important to highlight discrepancies between these two methods in the context of epidemiological research. Objective: The aim of this cross-sectional study is to assess the agreements between self-reported smoking status and nicotine metabolite detection. https://allfixelectricales.shop/product-category/rcd-mains-extension-lead/