Use of continine immunoassay test strips for preclassifying urine samples from smokers and nonsmokers prior to analysis by LC-MS-MS

J Anal Toxicol. 2005 Nov-Dec;29(8):814-8. doi: 10.1093/jat/29.8.814.


Cotinine biomarker measurements involving both smokers and nonsmokers must accommodate a broad range of concentrations. Thus, we have routinely preclassified unknown samples as being either "high" or "low" by using an enzyme-linked immunoassay for cotinine prior to analysis by tandem mass spectrometry (MS). Although this method is effective, it is also time-consuming and complex; a simpler and faster approach would be useful. Consequently, a screening assay for urine cotinine using an immunochromatographic test strip (NicAlert) followed by a computerized analysis of the data was examined as a possible alternative. The results indicate that this approach can provide useful classification efficiency when using our target cutoff value of approximately 20 ng/mL. In the analysis of 50 urine samples from nonsmokers with varying degrees of exposure to environmental tobacco smoke, the classification sensitivity and specificity were 88% and 92%, respectively, for cotinine measured by the test strips relative to total cotinine concentrations measured by atmospheric-pressure ionization tandem MS. However, the relatively high cost of the strips may be a limiting factor.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calibration
  • Chromatography, Liquid
  • Cotinine / urine*
  • Humans
  • Hydrogen-Ion Concentration
  • Immunoassay
  • Reagent Strips*
  • Smoking / urine*
  • Spectrometry, Mass, Electrospray Ionization
  • Tobacco Smoke Pollution*


  • Reagent Strips
  • Tobacco Smoke Pollution
  • Cotinine