Rasmussen Louise, Herzog Marielle, Rømer Eva, Micallef Jake, Bulut Orhan, Wilhelmsen Michael, Christensen Ib Jarle, Nielsen Hans J
a Department of Surgical Gastroenterology , Hvidovre Hospital, University of Copenhagen , Hvidovre , Denmark ;
b Belgian Volition SA, Rue du Séminaire 20A, Centre Technologique , Namur , Belgium ;
Scand J Clin Lab Invest. 2016 Oct;76(6):448-53. doi: 10.1080/00365513.2016.1190862. Epub 2016 Jun 13.
To evaluate pre-analytical variables of circulating cell-free nucleosomes containing 5-methylcytosine DNA (5mC) or histone modification H3K9Me3 (H3K9Me3).
Six studies were designed to assess the possible influence of pre-analytical variables. Study 1: influence of stasis and contamination with white-cells and platelets. Study 2: influence of within-day variations. Study 3: influence of day-to-day variation. Study 4: influence of temperature during handling and storage, and of neoplastic disease. Study 5: influence of colonoscopy. Study 6: influence of the surgical trauma. 5mC and H3K9Me3 measurements were performed using enzyme-linked immunosorbent assays.
Stasis, white-cell and platelet contamination, within-day variations, varying storage time before centrifugation, colonoscopy, and surgical trauma had no significant influence on levels of 5mC or H3K9Me3. Day-to-day variations of 12.7% and 11.5% (intra-individual) and 98.1% and 60.8% (inter-individual) were shown for 5mC and H3K9Me3, respectively. Levels of 5mC or H3K9Me3 were significantly higher in samples stored at room temperature until centrifugation compared to samples stored on ice. Patients with cancer had significantly lower levels of 5mC or H3K9Me3 compared to levels in healthy individuals.
Levels of 5mC or H3K9Me3 appear stable in most pre-analytical settings if blood samples are stored at room temperature until centrifugation.
评估含有5-甲基胞嘧啶DNA（5mC）或组蛋白修饰H3K9Me3（H3K9Me3）的循环游离核小体的分析前变量。
设计了六项研究来评估分析前变量的可能影响。研究1：停滞以及白细胞和血小板污染的影响。研究2：日内变化的影响。研究3：日间变化的影响。研究4：处理和储存期间温度以及肿瘤疾病的影响。研究5：结肠镜检查的影响。研究6：手术创伤的影响。使用酶联免疫吸附测定法进行5mC和H3K9Me3测量。
停滞、白细胞和血小板污染、日内变化、离心前不同的储存时间、结肠镜检查和手术创伤对5mC或H3K9Me3水平没有显著影响。5mC和H3K9Me3的日间变化分别显示为12.7%和11.5%（个体内）以及98.1%和60.8%（个体间）。与冰上储存的样本相比，室温储存直至离心的样本中5mC或H3K9Me3水平显著更高。与健康个体相比，癌症患者的5mC或H3K9Me3水平显著更低。
如果血样在室温下储存直至离心，在大多数分析前情况下，5mC或H3K9Me3水平似乎是稳定的。
