Urinary point-of-care test for smoking in the pre-operative assessment of patients undergoing elective plastic surgery

Abstract

Self-reported information about smoking habit and cigarette consumption can be inaccurate and subject to bias in the clinical setting. Accurate assessment of a given smoking history at point-of-care is valuable. We describe the use of a comprehensive smoking questionnaire and the use of a disposable biomarker test to verify and quantify the exposure to tobacco smoke. This point-of-care test (SmokeScreen) is a 6-min, easy-to-use urine test that measures nicotine and its breakdown products. One hundred consecutive patients attending plastic surgery pre-assessment clinic filled in the questionnaire and gave a consented urine sample. Qualitative and semi-quantitative assessment of tobacco consumption was observed by a simple sample colour change set against a standardised colorimetric chart for nicotine metabolite containing urine. The questionnaire self-reported smoking prevalence was 30% with 98% test specificity. The cotinine validated smoking prevalence was 54% with a 26% self-denial rate. Half the patients (n = 15) who admitted smoking on the questionnaire underreported the amount they smoked daily, as quantified by biochemical measurement. Objective biochemical assessment shows that 26% of self-reporting non-smokers via self-completed questionnaire studies are actual smokers attending this pre-assessment clinic. When patients did report smoking there was consistent underreporting of cigarette consumption.