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Evaluation of Serum Cotinine Cut-Off to Distinguish Smokers From Nonsmokers in the Korean Population

View Article: PubMed Central - PubMed

ABSTRACT

Background: Cotinine has been widely used as an objective marker to identify current smokers. We conducted this study to address the absence of Korean studies investigating the efficacy of immunoassays and liquid chromatography–tandem mass spectrometry (LC-MS/MS) for the detection of serum cotinine and to determine the optimal serum cotinine cut-off level for differentiating current smokers from nonsmokers.

Methods: Serum specimens were obtained from 120 subjects. They were randomly chosen to represent a broad distribution of urine cotinine levels based on a retrospective review of questionnaires and results of urine cotinine levels. We determined serum cotinine levels using the IMMULITE 2000 XPi Immunoassay System (Siemens Healthcare Diagnostics Inc., USA) and LC-MS/MS (API-4000, Applied Biosystems, USA). Correlation was analyzed between IMMULITE serum cotinine, urine cotinine, and LC-MS/MS serum cotinine levels. ROC curve was analyzed to identify the optimal IMMULITE serum cotinine cut-off level for differentiating current smokers from nonsmokers.

Results: IMMULITE serum cotinine levels correlated with both urine cotinine and LC-MS/MS serum cotinine levels, with correlation coefficients of 0.958 and 0.986, respectively. The optimal serum cotinine cut-off level for distinguishing current smokers from nonsmokers was 13.2 ng/mL (95.7% sensitivity, 94.1% specificity) using IMMULITE.

Conclusions: This is the first study to investigate the use of LC-MS/MS for the measurement of serum cotinine and to determine the optimal serum cotinine cut-off level for the IMMULITE immunoassay. Our results could provide guidelines for differentiating current smokers from nonsmokers in the Korean population.

No MeSH data available.


ROC curve analysis of IMMULITE serum cotinine levels for differentiating current smokers from nonsmokers.Abbreviations: AUC, area under the curve; CI, confidence interval.
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Figure 3: ROC curve analysis of IMMULITE serum cotinine levels for differentiating current smokers from nonsmokers.Abbreviations: AUC, area under the curve; CI, confidence interval.

Mentions: The optimal IMMULITE serum cotinine cut-off level for distinguishing smokers from nonsmokers was 13.2 ng/mL, with 95.7% sensitivity (95% confidence interval [CI], 87.0-98.9%), 94.1% specificity (95% CI, 82.8-98.5%), 95.7% positive predictive value (PPV), and 94.1% negative predictive value (NPV). The area under the curve (AUC) was 0.954 (95% CI, 0.910-0.998) (Fig. 3).


Evaluation of Serum Cotinine Cut-Off to Distinguish Smokers From Nonsmokers in the Korean Population
ROC curve analysis of IMMULITE serum cotinine levels for differentiating current smokers from nonsmokers.Abbreviations: AUC, area under the curve; CI, confidence interval.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940485&req=5

Figure 3: ROC curve analysis of IMMULITE serum cotinine levels for differentiating current smokers from nonsmokers.Abbreviations: AUC, area under the curve; CI, confidence interval.
Mentions: The optimal IMMULITE serum cotinine cut-off level for distinguishing smokers from nonsmokers was 13.2 ng/mL, with 95.7% sensitivity (95% confidence interval [CI], 87.0-98.9%), 94.1% specificity (95% CI, 82.8-98.5%), 95.7% positive predictive value (PPV), and 94.1% negative predictive value (NPV). The area under the curve (AUC) was 0.954 (95% CI, 0.910-0.998) (Fig. 3).

View Article: PubMed Central - PubMed

ABSTRACT

Background: Cotinine has been widely used as an objective marker to identify current smokers. We conducted this study to address the absence of Korean studies investigating the efficacy of immunoassays and liquid chromatography–tandem mass spectrometry (LC-MS/MS) for the detection of serum cotinine and to determine the optimal serum cotinine cut-off level for differentiating current smokers from nonsmokers.

Methods: Serum specimens were obtained from 120 subjects. They were randomly chosen to represent a broad distribution of urine cotinine levels based on a retrospective review of questionnaires and results of urine cotinine levels. We determined serum cotinine levels using the IMMULITE 2000 XPi Immunoassay System (Siemens Healthcare Diagnostics Inc., USA) and LC-MS/MS (API-4000, Applied Biosystems, USA). Correlation was analyzed between IMMULITE serum cotinine, urine cotinine, and LC-MS/MS serum cotinine levels. ROC curve was analyzed to identify the optimal IMMULITE serum cotinine cut-off level for differentiating current smokers from nonsmokers.

Results: IMMULITE serum cotinine levels correlated with both urine cotinine and LC-MS/MS serum cotinine levels, with correlation coefficients of 0.958 and 0.986, respectively. The optimal serum cotinine cut-off level for distinguishing current smokers from nonsmokers was 13.2 ng/mL (95.7% sensitivity, 94.1% specificity) using IMMULITE.

Conclusions: This is the first study to investigate the use of LC-MS/MS for the measurement of serum cotinine and to determine the optimal serum cotinine cut-off level for the IMMULITE immunoassay. Our results could provide guidelines for differentiating current smokers from nonsmokers in the Korean population.

No MeSH data available.