Objective: To evaluate the effect of the storage time and temperature on the differential detection rate of nucleic acid test (NAT) of positive sample for low [3 times of limit of detection (LOD)] and extremely low concentration [0.5 times of limit of detection (LOD)] HIV-1 so as to select a suitable storage condition for the sample before discrimination detection of nucleic acid. Methods: The positive HIV-1 sample with two concentrations (60 IU/mL and 5IU/mL) were stored at 3 kinds of temperatures (4℃、-20℃ and -80℃) for 7 days, respectively. The positive detection rate of the samples were stored in 0 day was considered as the control of the test. At the 0 d and 7 d of 60 IU/mL and the 1d, 3d and 7d of 5 IU/mL, the identification detection reagent of Procleix Utrio Plus was used to carry out duplicate detection of 30 times for samples. The detection rate and its variation tendency of positive sample of HIV-1 under different storage condition were recorded and compared. Results: For the HIV-1 sample of 60 IU/mL, all of the positive detection rates at 0d and 7d under 3 different temperatures were 100%. For the HIV-1 sample of 5 IU/mL, all of the positive detection rate at 0 d were more than 50%, and they were lower than 50% under 4℃ after these samples were stored 3 d. Although the detection rates of -20℃and -80℃ were decline after 3 d, they still were above 50%. And the positive detection rates of three kinds of temperatures after samples were stored 7d obviously decreased, and only the detection rate of stored 7d under -80℃ was coincidence with that of 0 d (it still was 56.67%). Besides, the difference of detection rate between stored 7d and 0 d under 4℃ was significant (x2=4.34, P<0.05). Conclusion: It is easily that the positive HIV-1 sample with extremely low concentration (0.5 times of LOD) was effected by environment factor, and they should be detected as early as possible. And they should be stored at-80℃ if they need be stored.%目的:评估保存时间和温度对低载量[3倍检测限(limit of detection,LOD)]和极低载量(0.5倍LOD)人类免疫缺陷病毒-1(HIV-1)阳性标本核酸检测(NAT)鉴别检出率的影响,选择适合的核酸鉴别检测前标本保存条件.方法:分别将60 IU/ml和5 IU/ml的HIV-1阳性标本于4 ℃、-20 ℃及-80 ℃的3种温度条件下保存7 d,以0 d保存标本的阳性检出率作为对照.当60 IU/ml标本保存0 d和7 d时以及5 IU/ml保存1 d、3 d和7 d时,使用Procleix Utrio Plus鉴别检测试剂对标本进行30次重复检测,记录和比较不同保存条件下HIV-1阳性标本的检出率及其变化趋势.结果:60 IU/ml HIV-1标本,在3种温度条件下0 d和7 d时HIV-1阳性检出率均为100%.5 IU/ml浓度的标本在0 d时均有50%以上的阳性检出率;保存3 d后,4 ℃内保存的标本阳性检出率下降至50%以下,-20 ℃及-80 ℃两个温度保存的标本的检出率虽有不同程度的下降,但仍保持50%以上的检出率;保存7 d后3种温度条件下标本的阳性检出率均明显下降,仅-80 ℃条件下阳性检出率与0 d对照一致,仍为56.67%,并且4 ℃条件下保存7 d的标本检出率与0 d的检出率比较,差异具有统计学意义(x2=4.34, P<0.05).结论:极低病毒载量(0.5倍LOD)的HIV-1阳性标本易受环境因素影响,应尽早完成核酸鉴别检测,如需保存应存放于-80 ℃条件下.
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