Highly sensitive immuno-assays for the determination of cotinine in serum and saliva. Comparison between RIA and an avidin-biotin ELISA.
Two immuno-assay methods (RIA and ELISA) have been developed for the accurate and sensitive measurement of cotinine in human body fluids (serum, saliva). RIA uses [3H]cotinine as antigen and charcoal/dextran for separating cotinine-bound antibodies from the free derivative. Another technique (ELISA) was developed to avoid the use of radio-labelled compounds and to determine cotinine in large populations, including passive or non-smokers who usually present very low concentrations. The two techniques were analytically validated. The detection limit was similar (0.1 micrograms/l) and the precision was better than 10% for both techniques. Non-smoker values ranged from 0.1 to 17 micrograms/l by ELISA and 0.1 to 27.5 micrograms/l by RIA, whereas smoker values ranged from 50 to 1000 micrograms/l (ELISA) and from 70 to 800 micrograms/l (RIA). The comparative analysis of cotinine in 96 human sera revealed a good correlation between the two methods (r = 0.97) and a reliable discrimination between the populations of non-smokers and smokers. As usual, the ELISA is more rapid (4 h 30 min) than the RIA (longer than 48 h). ELISA is proposed for use in the epidemiological investigation of the human tobacco risk.
Benkirane
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S
Laboratoire du Centre de Médecine Préventive, (URA CNRS 597), Vandoeuvre-lès-Nancy, France.
Nicolas
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A
Galteau
M M
MM
Siest
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G
D001360:Avidin; D001710:Biotin; D003367:Cotinine / Q000032:analysis* / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007202:Indicators and Reagents; D011863:Radioimmunoassay / Q000379:methods; D012016:Reference Values; D012463:Saliva / Q000737:chemistry*
D007202:Indicators and Reagents; D001360:Avidin; D001710:Biotin; D003367:Cotinine