Garde A H, Hansen A M
National Institute of Occupational Health, Copenhagen, Denmark.
Scand J Clin Lab Invest. 2005;65(5):433-6. doi: 10.1080/00365510510025773.
The measurement of salivary cortisol provides a simple, non-invasive, and stress-free measure frequently used in studies of the hypothalamic-pituitary-adrenal axis activity. In research projects, samples are often required to be stored for longer periods of time either because of the protocol of the project or because of lack of funding for analysis. The aim of the present study was to explore the effects of long-term storage of samples on the amounts of measurable cortisol. Ten pools of saliva were collected on polyester Salivette tampons from five subjects. After centrifugation the samples were either stored in small vials or spiked to polyester Salivette tampons before analysis for cortisol using Spectria RIA kits. The effects of storage were evaluated by a linear regression model (mixed procedure) on a logarithmic scale. No effects on cortisol concentrations were found after storage of saliva at 5 degrees C for up to 3 months or at -20 degrees C and -80 degrees C for up to one year. In contrast, concentrations of cortisol were found to decrease by 9.2% (95% confidence interval (CI): 3.8%; 14.3%) per month in samples stored at room temperature. Repeated freezing and thawing of samples up to four times before analysis did not affect the measured concentrations of cortisol. The coefficient of residual variation (CVresid) for samples stored on Salivette tampons were twice the CVresid for samples stored in separate vials after centrifugation. In conclusion, centrifuged saliva samples for analysis of cortisol may be stored at 5 degrees C for up to 3 months or at -20 degrees C or -80 degrees C for at least one year. However, long-term storage at room temperature cannot be recommended. Repeated cycles of freezing and thawing did not appear to affect the concentrations of cortisol.
唾液皮质醇的测量提供了一种简单、无创且无压力的测量方法，常用于下丘脑-垂体-肾上腺轴活动的研究。在研究项目中，由于项目方案或缺乏分析资金，样本通常需要长时间保存。本研究的目的是探讨样本长期保存对可测量皮质醇含量的影响。从五名受试者身上收集了10组唾液样本，置于聚酯唾液收集器棉塞上。离心后，样本要么保存在小瓶中，要么在使用Spectria RIA试剂盒分析皮质醇之前添加到聚酯唾液收集器棉塞上。通过对数尺度的线性回归模型（混合程序）评估保存的影响。在5℃下保存长达3个月或在-20℃和-80℃下保存长达一年后，未发现对皮质醇浓度有影响。相比之下，在室温下保存的样本中，皮质醇浓度每月下降9.2%（95%置信区间（CI）：3.8%；14.3%）。在分析前对样本进行多达四次的反复冻融不会影响所测皮质醇浓度。保存在唾液收集器棉塞上的样本的残余变异系数（CVresid）是离心后保存在单独小瓶中的样本的CVresid的两倍。总之，用于分析皮质醇的离心唾液样本可在5℃下保存长达3个月，或在-20℃或-80℃下保存至少一年。然而，不建议在室温下长期保存。反复冻融循环似乎不会影响皮质醇浓度。
