Chernesky Max, Jang Dan, Luinstra Kathy, Chong Sylvia, Smieja Marek, Cai Wenjie, Hayhoe Beth, Portillo Eder, Macritchie Cindy, Main Cheryl, Ewert Ruth
St. Joseph's Healthcare, 50 Charlton Avenue East, Hamilton, ON L8N 4A6, Canada.
J Clin Microbiol. 2006 Feb;44(2):400-5. doi: 10.1128/JCM.44.2.400-405.2006.
The clinical sensitivity of nucleic acid amplification tests may be determined by analytical sensitivity and inhibitors in patient samples. We established endpoints for detection of propagated Chlamydia trachomatis L2 434, diluted according to swab and urine protocols for APTIMA Combo 2 (AC2), ProbeTec ET (PT), and Amplicor (AMP) assays. AC2 was 1,000-fold more sensitive than PT and 10-fold more sensitive than AMP on mock swab specimens. For urine, AC2 analytical sensitivity was 100-fold greater than those of the other assays. Spiking an aliquot of each clinical-trial sample from 298 women demonstrated inhibition rates in first-void urine (FVU), cervical swabs (CS), and vaginal swabs (VS) of 12.1%, 12.8%, and 10.4% for AMP; 27.2%, 2%, and 2%, for PT; and 0.3%, 1.7%, and 1.3% for AC2. Inhibition of our C. trachomatis spike and the PT or AMP amplification controls from the manufacturers showed less than 50% correlation. Using an infected-patient reference standard (a specimen positive in at least two tests or a single test positive in two of three samples) in AC2, the VS identified 68/69 (98.6%) infected women compared to CS (89.9%) or FVU (81.2%). Significantly fewer women were identified by PT (65.2%, 63.8%, and 66.7%) or AMP (65.2%, 59.4%, and 56.5%) with the three specimens. By individual specimen type, AC2 confirmed virtually all PT- and AMP-positive specimens, but rates of AC2 confirmation by AMP or PT ranged from 62.9 to 80.3%. The AC2 test identified significantly more women infected with C. trachomatis (P = 0.001). Vaginal swabs appear to be the specimen of choice for screening.
核酸扩增检测的临床敏感性可能由分析敏感性和患者样本中的抑制剂决定。我们确定了传播型沙眼衣原体L2 434的检测终点，其按照APTIMA Combo 2（AC2）、ProbeTec ET（PT）和Amplicor（AMP）检测的拭子和尿液检测方案进行稀释。在模拟拭子样本上，AC2的敏感性比PT高1000倍，比AMP高10倍。对于尿液样本，AC2的分析敏感性比其他检测高100倍。对来自298名女性的每个临床试验样本的一份等分试样进行加样，结果显示AMP在首次晨尿（FVU）、宫颈拭子（CS）和阴道拭子（VS）中的抑制率分别为12.1%、12.8%和10.4%；PT的抑制率分别为27.2%、2%和2%；AC2的抑制率分别为0.3%、1.7%和1.3%。我们对沙眼衣原体加样物以及制造商的PT或AMP扩增对照的抑制显示，两者之间的相关性小于50%。在AC2检测中，使用感染患者参考标准（在至少两项检测中呈阳性的样本或三个样本中有两个呈阳性的单次检测样本），VS检测出68/69（98.6%）名感染女性，而CS的检测率为89.9%，FVU的检测率为81.2%。PT（65.2%、63.8%和66.7%）或AMP（65.2%、59.4%和56.5%）对这三种样本检测出的感染女性明显较少。按单个样本类型来看，AC2几乎确认了所有PT和AMP阳性样本，但AMP或PT对AC2的确认率在62.9%至80.3%之间。AC2检测出的感染沙眼衣原体的女性明显更多（P = 0.001）。阴道拭子似乎是筛查的首选样本。
