F I Proctor Foundation, University of California San Francisco, San Francisco, California 94143-0412, USA.
Invest Ophthalmol Vis Sci. 2011 Aug 3;52(9):6133-7. doi: 10.1167/iovs.11-7419.
Tests for ocular Chlamydia trachomatis have not been well characterized, because there is no gold standard test. Latent class analysis (LCA) was performed to estimate the sensitivity and specificity of laboratory and clinical tests for trachoma in the absence of a gold standard.
Individual data from pretreatment, hyperendemic areas in Ethiopia were used. A clustered LCA was performed for three diagnostic tests: PCR and WHO simplified criteria grades of follicular trachoma (TF) and intense trachomatous inflammation (TI).
Data from 2111 subjects in 40 villages were available. TF was estimated to be 87.3% (95% CI, 83.3-90.1) sensitive and 36.6% (95% CI, 23.6-40.3) specific; TI was estimated to be 53.6% (95% CI, 46.1-88.0) sensitive and 88.3% (95% CI, 83.3-92.0) specific, and PCR was estimated to be 87.5% (95% CI, 79.9-97.2) sensitive and 100% (95% CI 69.3-100) specific.
LCA allows for an estimate of test characteristics without prior assumption of their performance. TF and TI were found to act in a complementary manner: TF is a sensitive test and TI is a specific test. PCR is highly specific but lacks sensitivity. The performance of these tests may be due to the time course of ocular chlamydial infection, and for this reason, results may differ in areas of low prevalence or recent mass treatment (ClinicalTrials.gov number, NCT00221364).
由于缺乏金标准检测方法，针对眼型沙眼衣原体的检测方法尚未得到充分验证。本研究采用潜类别分析（LCA）方法，旨在评估在无金标准检测方法的情况下，实验室和临床检测沙眼的敏感性和特异性。
本研究使用了来自埃塞俄比亚高度流行地区的预处理个体数据。对三种诊断性检测方法（PCR 和世界卫生组织简化的滤泡性沙眼（TF）和重度沙眼炎症（TI）分级标准）进行聚类 LCA。
在 40 个村庄中，共纳入 2111 名受试者，结果显示 TF 的敏感性为 87.3%（95%可信区间：83.3%-90.1%），特异性为 36.6%（95%可信区间：23.6%-40.3%）；TI 的敏感性为 53.6%（95%可信区间：46.1%-88.0%），特异性为 88.3%（95%可信区间：83.3%-92.0%）；PCR 的敏感性为 87.5%（95%可信区间：79.9%-97.2%），特异性为 100%（95%可信区间：69.3%-100%）。
LCA 可在不预先假设检测性能的情况下，对检测特征进行估计。TF 和 TI 具有互补性：TF 是一种敏感性检测方法，TI 是一种特异性检测方法。PCR 具有高度特异性，但缺乏敏感性。这些检测方法的性能可能与眼部沙眼衣原体感染的时间过程有关，因此，在低流行地区或近期大规模治疗时，结果可能会有所不同（临床试验注册号：NCT00221364）。
