Gynecologic Cancer Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Asian Pac J Cancer Prev. 2021 Nov 1;22(11):3441-3445. doi: 10.31557/APJCP.2021.22.11.3441.
HPV detection has been proposed as part of the co-testing which improves the sensitivity of cervical screening. However, the commercially liquid-based medium adds cost in low-resource areas. This study aimed to evaluate the performance of ice-cold phosphate buffer saline (PBS) for HPV detection.
HPV DNA from SiHa cells (with 1-2 copies of HPV16 per cell) preserved in ice-cold PBS or PreserveCyt solution at different time points (24, 36, 48, 72, 120 and 168 h) was tested in triplicate using Cobas 4800. The threshold cycle (Ct) values of both solutions were compared. An estimated false negative rate of PBS was also assessed by using the difference in Ct values between both solutions (∆Ct) and Ct values of HPV16-positive PreserveCyt clinical samples (Ctsample) at corresponding time points. Samples with a (Ctsample+∆Ct) value > 40.5 (the cutoff of HPV16 DNA by Cobas 4800) were considered as false negativity.
The Ct values of HPV16 DNA of SiHa cells collected in PBS were higher than PreserveCyt ranging from 0.43 to 2.36 cycles depending on incubation times. There was no significant difference at 24, 72, 120, and 168 h. However, the Ct values were statistically significantly higher for PBS than PreserveCyt at 36 h (31.00 vs 29.26), and 48 h (31.06 vs 28.70). A retrospective analysis in 47 clinical PreserveCyt collected samples that were positive for HPV16 DNA found that 1 case (2%) would become negative if collected in ice-cold PBS.
The PBS might be an alternative collecting medium for HPV detection in the low-resource areas. Further evaluations are warranted.
HPV 检测已被提议作为联合检测的一部分，以提高宫颈筛查的灵敏度。然而，商业上使用的液基介质会增加资源匮乏地区的成本。本研究旨在评估冰磷酸盐缓冲盐水（PBS）用于 HPV 检测的性能。
使用 Cobas 4800 对保存在冰 PBS 或 PreserveCyt 溶液中的 SiHa 细胞（每个细胞有 1-2 个 HPV16 拷贝）的 HPV DNA 进行检测，分别在 24、36、48、72、120 和 168 小时时重复三次。比较两种溶液的阈值循环（Ct）值。还通过比较两种溶液之间的 Ct 值差异（∆Ct）和相应时间点 HPV16 阳性 PreserveCyt 临床样本的 Ct 值（Ctsample）来评估 PBS 的估计假阴性率。（Ctsample+∆Ct）值>40.5（Cobas 4800 检测 HPV16 DNA 的截止值）的样本被认为是假阴性。
保存在 PBS 中的 SiHa 细胞的 HPV16 DNA 的 Ct 值高于 PreserveCyt，取决于孵育时间，范围从 0.43 到 2.36 个周期。在 24、72、120 和 168 小时时，没有显著差异。然而，在 36 小时（31.00 与 29.26）和 48 小时（31.06 与 28.70）时，PBS 的 Ct 值明显高于 PreserveCyt。对 47 例临床 PreserveCyt 采集的 HPV16 DNA 阳性样本进行的回顾性分析发现，如果用冰 PBS 采集，1 例（2%）会变成阴性。
PBS 可能是资源匮乏地区 HPV 检测的替代采集介质。需要进一步评估。
