Conklin Quinn A, Smith Dana L, Dai Guorui, King Brandon G, Saron Clifford D, Lin Jue
Center for Mind and Brain, University of California, Davis, Davis, California, USA.
Department of Psychiatry, Center for Health and Community, University of California, San Francisco, San Francisco, California, USA.
Am J Hum Biol. 2025 Sep;37(9):e70128. doi: 10.1002/ajhb.70128.
Telomere length (TL) is a valuable marker of aging and stress that reflects both genetic and environmental influences. Quantitative PCR (qPCR) TL measurement is a powerful and cost-effective assay, especially in population studies with limited quantities of source material. Nevertheless, collecting and transporting high-quality blood samples can be logistically challenging, and research suggests that several preanalytical and analytical factors can influence the reliability and precision of the qPCR assay. Here we describe a procedure for collecting blood remotely in a large-scale study. We then assess the influence of various features of the samples, as well as their collection, transportation, and storage on DNA quality and TL assay outcomes.
Participants used at-home collection kits to collect a few drops of whole blood in BD Microtainers during a baseline (n = 265) and 1-year follow-up (n = 178) assessment. DNA was extracted using a magnetic-bead method, and DNA yield, purity, and integrity were assessed. TL was measured using qPCR. To assess inter-assay variation, the coefficient of variation (CV) was calculated across repeated TL measurements (three runs) for each sample. When there was adequate material for duplicate extractions of DNA from the same blood samples, we calculated the intra-class correlation (ICC) of the resultant TL values to assess assay precision.
Our analyses revealed that as little as 50 μL of blood yielded sufficient DNA for highly precise TL measurement (ICC = 0.962, n = 365). Transportation time and an additional year of storage time at -80°C did not meaningfully affect DNA quality or assay outcomes. However, blood clotting was associated with longer telomere estimates, whereas greater temperature exposure was related to shorter telomere estimates.
We established that whole blood collected remotely in BD Microtainers can provide a valid sample source for qPCR TL measurement. We also outline important logistical considerations related to sample collection and handling and provide recommendations for researchers who want to use this method.
端粒长度（TL）是衰老和应激的一个重要标志物，反映了遗传和环境的影响。定量聚合酶链反应（qPCR）测量端粒长度是一种强大且经济高效的检测方法，尤其适用于源材料数量有限的人群研究。然而，收集和运输高质量血液样本在后勤方面可能具有挑战性，并且研究表明，一些分析前和分析因素会影响qPCR检测的可靠性和精度。在此，我们描述了在一项大规模研究中远程采集血液的程序。然后，我们评估样本的各种特征以及它们的采集、运输和储存对DNA质量和端粒长度检测结果的影响。
在基线（n = 265）和1年随访（n = 178）评估期间，参与者使用家用采集试剂盒在BD微量采血管中采集几滴全血。使用磁珠法提取DNA，并评估DNA产量、纯度和完整性。使用qPCR测量端粒长度。为了评估检测间的变异，计算每个样本重复端粒长度测量（三次运行）的变异系数（CV）。当有足够的材料从相同血液样本中重复提取DNA时，我们计算所得端粒长度值的组内相关性（ICC）以评估检测精度。
我们的分析表明，仅50 μL血液就能产生足够的DNA用于高精度的端粒长度测量（ICC = 0.962，n = 365）。运输时间和在-80°C下额外一年的储存时间对DNA质量或检测结果没有显著影响。然而，血液凝固与更长的端粒估计值相关，而更高的温度暴露与更短的端粒估计值相关。
我们确定，在BD微量采血管中远程采集的全血可为qPCR端粒长度测量提供有效的样本来源。我们还概述了与样本采集和处理相关的重要后勤考虑因素，并为希望使用此方法的研究人员提供建议。
