不同处理和保存条件下体外HCV RNA稳定性研究

Stability of Hepatitis C Virus RNA in Various Processing and Storage Conditions

对献血者或病人进行HCV核酸检测时，如果标本的采集、处理、保存不当，会造成病毒核酸降解，从而影响检测结果的真实性。本研究的目的是对不同抗凝剂、不同温度、不同保存时间下的HCV RNA病毒稳定性进行研究，以考察常规采供血过程中，标本采集及保存方式对NAT检测的影响。采集7例HCV RNA阳性献血者的血样，采用不同的抗凝剂、经不同的温度和不同的时间保存后，采用荧光定量PCR方法测定HCV RNA病毒含量，考察HCV RNA的稳定性。结果表明：①不同抗凝剂抗凝的全血于4℃保存48小时过程中，病毒含量下降至原滴度的42．7％；EDTA抗凝组各时间点的滴度均低于其它3组（分别相当于其它3组的67．6％-25．1％）。②ACD抗凝的全血在4、25和37℃保存48小时．病毒含量分剐下降到原滴度的53．8％、72．5％、29．8％。③ACD抗凝的全血离心分离出血浆，4℃或25℃继续保存7天，病毒含量分别下降至原滴度的70．9％和25．1％。④ACD抗凝的全血分离的血浆，反复冻融4次，病毒含量下降到原滴度的38．9％。结论：①用于核酸检测的标本应该用无菌采血管采样；②在无菌采血管采样的前提下，核酸检测标本用未抗凝血、EDTA、ACD、CPDA抗凝血均可；③采集的全血应避免放置37℃以上，ACD抗凝全血在4℃、25℃保存48小时内、37℃保存14小时内，HCV RNA病毒仍较为稳定；④分离后的血浆应避免放置25℃以上，ACD抗凝全血分离后的血浆在4℃保存7天，25℃保存3天，HCV RNA病毒仍比较稳定；⑤血浆标本应避免多次冻融，但冻融3次的血浆HCV RNA病毒含量仍然较为稳定；⑥无菌采样对维持病毒的稳定性非常重要；单纯的机械性溶血并不会明显导致病毒的降解；只要注意无菌的问题和有合适的核酸提取方法去除血红素，HCV RNA病毒实际上比以前认为的要稳定得多。

The study was purposed to investigate whether processing and storage conditions might influence the stability of the HCV RNA in whole blood or in plasma. The samples obtained from seven patients known to be positive for HCV RNA were kept in different storage conditions with different anticoagulants, and at the end of processing the plasma samples were frozen at - 80℃ until fluorescent quantitative PCR testing. The results showed that there was no significant loss of HCV RNA titers in whole blood anticoagulated with CPDA or ACD or EDTA or none（ P 〉 0.05 ）, while differences in comparison of the EDTA-anticoagulant storage condition with three other anticoagulants storage conditions at 4℃ after 48 hours were significant （ P 〈 0.05 ）. The HCV RNA level decreased to 53.8% ,72.5% and 29.8% after 48 hours of storage of whole blood anticoagulated with ACD at 4℃, 25℃ and 37℃ respectively. The HCV RNA level of plasma samples stored at4℃ and at 25℃ （room temperature） after 7 days decreased to 70.9% and 25.1% respectively. After four freeze-thaw cycles the HCV RNA level decreased 38.9% in plasma samples. It is concluded that the HCV RNA is stable relatively. The HCV RNA is resistant to degradation under routine laboratory handling and storage conditions or blood collection, transport and processing conditions. The influence of different anticoagulants on the stability of HCV RNA is different. Blood samples would better be stored at 4℃ after collection and plasma separated within 48 hours. And it is important for the stability of HCV RNA undergoing asepsis blood collection process. HCV RNA remains stable at 4℃ for at least 7 days or at room temperature for 3 days, allowing greater flexibility in samples collection and transport in transfusion practice nowadays. HCV RNA in plasma samples subject to up to three short-term freeze-thaw cycles is still stable.