Riboli E, Haley N J, De Waard F, Saracci R
International Agency for Research on Cancer, Lyon, France.
Int J Epidemiol. 1995 Apr;24(2):354-8. doi: 10.1093/ije/24.2.354.
The utility of using biomarkers of smoking in epidemiological studies depends not only on the validity and precision of the laboratory procedure but often on the long-term stability of the analytes of interest in stored biological samples.
We retrieved urine samples collected in 1976-1977 from women included in a cohort study in Utrecht and for whom information on smoking status was available. Creatinine and thiocyanate were measured in 1976-1977 on fresh samples. Cotinine and creatinine were analysed in 1988 on urine stored at -20 degrees C.
Measurements of creatinine more than 10 years apart showed a correlation of 0.95 and equal means. Cotinine measurements made in 1988 allowed a clear separation of smokers and non-smokers (sensitivity 92%, specificity 100%), suggesting that concentrations retained their discriminant value even after 10 years of storage.
These results emphasize the possibilities offered by long-term storage, under proper conditions, of biological samples for subsequent determination of analytes which may emerge as the study progresses.
在流行病学研究中使用吸烟生物标志物的效用不仅取决于实验室程序的有效性和精确性，还常常取决于所关注分析物在储存生物样本中的长期稳定性。
我们从乌得勒支一项队列研究中纳入的女性那里获取了1976 - 1977年收集的尿液样本，这些女性有吸烟状况信息。1976 - 1977年对新鲜样本测量了肌酐和硫氰酸盐。1988年对储存在 - 20℃的尿液分析了可替宁和肌酐。
相隔10多年的肌酐测量显示相关性为0.95且均值相等。1988年进行的可替宁测量能够清晰区分吸烟者和非吸烟者（敏感性92%，特异性100%），这表明即使储存10年后，浓度仍保持其判别价值。
这些结果强调了在适当条件下长期储存生物样本以便后续测定随着研究进展可能出现的分析物所带来的可能性。
