Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, Hannover, Germany.
BMC Vet Res. 2020 Dec 17;16(1):487. doi: 10.1186/s12917-020-02698-5.
Because of fast leucocyte degeneration in cerebrospinal fluid (CSF) laboratory examinations of CSF samples should be performed approximately within 30 min after withdrawal. This study examines the storage of canine and feline CSF samples in "TransFix®/EDTA CSF Sample Storage Tubes" (Cytomark, Buckingham, UK) for preventing leucocytes from degeneration, so that routine and flow cytometry examinations are feasible up to 3 days after sampling.
After storage in TransFix® tubes, leukocytes could not be adequately stained with Türk's solution and differentiating between erythrocytes and leukocytes was cumbersome. In addition, the cell morphology could not be sufficiently assessed on cytospin preparations because of shrunken leukocytes and indistinct cell nuclei. In contrast, by flow cytometry, a significantly higher cell count was measured over the entire study period in the samples stored in TransFix® tubes compared to the untreated samples. The antibodies (AB) against CD3, CD4 and CD21, against CD11b and against CD45 showed a good binding strength and thus enabled a good differentiation of cell populations. However, after storage in the TransFix® tubes, monocytes were no longer detectable using an AB against CD14.
Based on these results, "TransFix®/EDTA CSF Sample Storage Tubes" can be used for extended storage prior to flow cytometric analysis of lymphocytes and granulocytes in CSF samples but not for detecting monocytes. However, standard examinations, such as microscopic cell counting and morphological cell assessment should be performed on fresh CSF samples.
由于脑脊液（CSF）实验室检查中的白细胞迅速变性，因此 CSF 样本的采集后应在大约 30 分钟内进行检测。本研究通过将犬和猫的 CSF 样本储存在“TransFix®/EDTA CSF 样本储存管”（Cytomark，英国 Buckingham）中，以防止白细胞变性，从而使常规和流式细胞术检查在采样后 3 天内成为可能。
在 TransFix®管中储存后，无法用 Türk 溶液充分染色白细胞，且区分红细胞和白细胞很麻烦。此外，由于白细胞皱缩且细胞核不清晰，在细胞离心涂片上无法充分评估细胞形态。相比之下，在整个研究期间，与未经处理的样本相比，储存在 TransFix®管中的样本通过流式细胞术测量的细胞计数显著更高。针对 CD3、CD4 和 CD21、CD11b 和 CD45 的抗体（AB）显示出良好的结合强度，从而能够很好地区分细胞群。然而，在 TransFix®管中储存后，使用针对 CD14 的 AB 不再能检测到单核细胞。
基于这些结果，“TransFix®/EDTA CSF 样本储存管”可用于流式细胞术分析 CSF 样本中的淋巴细胞和粒细胞之前的延长储存，但不能用于检测单核细胞。然而，应在新鲜 CSF 样本上进行标准检查，如显微镜下的细胞计数和形态学细胞评估。
