Castriciano S, Luinstra K, Jang D, Patel J, Mahony J, Kapala J, Chernesky M
Hamilton Regional Laboratory Medicine Program, and the Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, McMaster University, Hamilton, Ontario, Canada L8N 4A6.
J Clin Microbiol. 2002 Jul;40(7):2632-4. doi: 10.1128/JCM.40.7.2632-2634.2002.
Nucleic acid amplification assays such as the ligase chain reaction and PCR have encountered reproducibility problems. The initial extract and a newly extracted aliquot of urine specimens (n = 120) which had signal-to-cutoff (S/CO) ratios above 0.80 by the LCx Chlamydia assay were retested. Nucleic acid was extracted from an additional urine sample for testing by the AMPLICOR PCR Chlamydia assay. Fifteen percent (18 of 120) of the urine specimens were negative by all repeat tests (initial mean S/CO ratio by the LCx Chlamydia assay, 0.93; S/CO ratio range, 0.80 to 3.30). Repeat testing of the 102 specimens with possible positive results by the LCx Chlamydia assay by use of the initially extracted aliquot confirmed the results for 95 (93.1%) of the specimens; repeat testing of a newly extracted aliquot confirmed the results for 87 (85.3%) of the specimens. Twenty specimens had discordant results by the two repeat LCx Chlamydia assays. A total of 78 of 102 (76.5%) of the specimens were positive by the AMPLICOR PCR, and the AMPLICOR PCR confirmed the results for 82.1% (78 of 95) and 89.6% (78 of 87) of the specimens positive by the two repeat LCx Chlamydia assays, respectively. Some of the discrepancies observed by multiple repeat tests may have been due to specimen mislabeling or contamination during performance of the procedure rather than to the LCx Chlamydia assay. Both assays suffered from a lack of reproducibility on repeat testing with a small proportion of specimens, probably due to the presence of low levels of DNA, the presence of variable amounts of amplification inhibitors, and the loss of DNA during extraction.
诸如连接酶链反应和聚合酶链反应（PCR）等核酸扩增检测方法存在重复性问题。对最初提取物以及新提取的尿液标本等分试样（n = 120）进行重新检测，这些尿液标本通过LCx衣原体检测的信号与临界值（S/CO）比值高于0.80。从另外一份尿液样本中提取核酸，用于通过AMPLICOR PCR衣原体检测进行测试。所有重复检测中，15%（120份中的18份）尿液标本呈阴性（通过LCx衣原体检测的初始平均S/CO比值为0.93；S/CO比值范围为0.80至3.30）。对通过LCx衣原体检测可能呈阳性结果的102份标本，使用最初提取的等分试样进行重复检测，95份（93.1%）标本的结果得到确认；对新提取的等分试样进行重复检测，87份（85.3%）标本的结果得到确认。20份标本在两次重复的LCx衣原体检测中结果不一致。102份标本中有78份（76.5%）通过AMPLICOR PCR呈阳性，AMPLICOR PCR分别确认了两次重复LCx衣原体检测呈阳性的标本中82.1%（95份中的78份）和89.6%（87份中的78份）的结果。多次重复检测中观察到的一些差异可能是由于操作过程中标本误贴标签或污染，而非LCx衣原体检测本身的问题。两种检测方法在对一小部分标本进行重复检测时都缺乏可重复性，这可能是由于DNA水平较低、存在数量可变的扩增抑制剂以及提取过程中DNA的损失。
