保存温度及时间对化学发光法测定直接肾素浓度的影响

Effect of preservation temperature and time on chemiluminescence determination of direct renin concentration

目的研究样本保存温度及时间对血浆直接肾素浓度(DRC)的影响。方法采集乙二胺四乙酸二钾(EDTA-K2)抗凝血并分离血浆,于室温和冷藏均分别放置2、4、6、8h;冷冻4、8、12周;冷冻冻融1～3次后采用化学发光法测定DRC,与即刻值比较,差异率超过总变化极限值认为不可接受。结果室温放置2、4、6、8h的DRC均低于即刻值(P<0.05),差异率超过17%的样本比例分别为0、0、1/20、4/20;冷藏2、4、6、8h的DRC均高于即刻值(P<0.05),差异率超过17%的样本比例分别为0、2/20、4/20、11/20;冷冻12周内所有样本差异率均<17%;冻融2次时有1个样本降低超过17%。结论温度影响DRC稳定性,建议样本采集后室温6h内检测,否则应分离血浆冻存于-20℃可稳定12周,避免反复冻融。

Objective To study the effects of sample storage temperature and time on plasma direct renin concentration (DRC). Methods Potassium ethylenediaminetetraacetate (EDTA-K 2) anticoagulant boold was collected and plasma was separated.The plasma was stored at room temperature and refrigerated for 2,4,6 and 8 h,and frozen for 4,8 and 12 weeks.After freezing and thawing for 1 to 3 times,the chemiluminescence method was used to determine DRC.Compared with the instant value,the difference rate exceeding the total change limit was considered unacceptable. Results DRC values of 2,4,6 and 8 h at room temperature were lower than immediate values ( P < 0.05 ).The proportion of samples with difference rate over 17% was 0,0,1/20,4/20,respectively.DRC values of 2,4,6 and 8 h of refrigeration were higher than immediate value ( P < 0.05 ).The difference rate of all samples within 12 weeks of freezing was less than 17%.One sample decreased by more than 17% after freezing and thawing twice. Conclusion Temperature affects the stability of DRC.It is suggested that the samples should be detected within 6 hours after collection.Otherwise,the plasma should be frozen and stored at -20 ℃ for 12 weeks to avoid repeated freezing and thawing.