Gojković Amara, Vladimirov Sandra, Antonić Tamara, Bogavać-Stanojević Nataša, Novović Katarina, Spasojević-Kalimanovska Vesna, Filipić Brankica
University of Belgrade, Faculty of Pharmacy, Department of Medical Biochemistry, Belgrade.
University of Belgrade, Institute of Molecular Genetics and Genetic Engineering, Belgrade.
J Med Biochem. 2024 Jun 15;43(4):413-423. doi: 10.5937/jomb0-40360.
The pre-analytical (PA) phase is the most vulnerable phase of the laboratory testing procedure, with critical procedures-collection, handling, sample transport, and time and temperature of sample storage. This study aimed to examine the stability of basic biochemical parameters depending on the samples' storage conditions and the number of freeze-thaw cycles (FTCs). In parallel, the presence of sample bacterial contamination during routine laboratory work was examined.
Two plasma pools (ethylenediaminetetraacetic acid (EDTA), and sodium-fluoride/potassium oxalate plasma (NaF)) were stored at +4 ˚C/-20 ˚C. Total chole - sterol (TC), glucose, triglycerides (TG), urea, and albumin concentrations were measured using BioSystems reagents (cholesterol oxidase/peroxidase, glucose oxidase/per - oxidase, glycerol phosphate oxidase/peroxidase, urease/ salicylate, and bromcresol green method, respectively) on Ilab 300+. Sample bacterial contamination was determined by 16S rRNA sequence analysis. The expe - riment encompassed a 5 day-period: Day 1-fresh sample, Day 2-1st FTC, Day 3-2nd FTC, Day 4-3rd FTC, Day 5-4th FTC. The appearance of bacteria in two consecutive samples was the experiment's endpoint.
分析前（PA）阶段是实验室检测过程中最易受影响的阶段，涉及关键步骤——样本采集、处理、运输以及储存的时间和温度。本研究旨在根据样本的储存条件和冻融循环次数（FTCs）来检测基本生化参数的稳定性。同时，还对常规实验室工作期间样本细菌污染情况进行了检测。
将两个血浆混合样本（乙二胺四乙酸（EDTA）血浆和氟化钠/草酸钾血浆（NaF））分别储存在+4℃和-20℃环境下。使用BioSystems试剂（分别采用胆固醇氧化酶/过氧化物酶法、葡萄糖氧化酶/过氧化物酶法、甘油磷酸氧化酶/过氧化物酶法、脲酶/水杨酸盐法和溴甲酚绿法）在I lab 300+仪器上测定总胆固醇（TC）、葡萄糖、甘油三酯（TG）、尿素和白蛋白浓度。通过16S rRNA序列分析确定样本细菌污染情况。实验为期5天：第1天——新鲜样本，第2天——第1次冻融循环，第3天——第2次冻融循环，第4天——第3次冻融循环，第5天——第4次冻融循环。连续两个样本中出现细菌为实验终点。
