How reliable are tests for trachoma? - A latent class approach

Craig W. See, Wondu Alemayehu, Muluken Melese, Zhaoxia Zhou, Travis C. Porco, Stephen Shiboski, Bruce D. Gaynor, John Eng, Jeremy D. Keenan, Thomas M. Lietman

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


PURPOSE. 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. METHODS. 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). RESULTS. 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. CONCLUSIONS. 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 ( number, NCT00221364).

Original languageEnglish (US)
Pages (from-to)6133-6137
Number of pages5
JournalInvestigative Ophthalmology and Visual Science
Issue number9
StatePublished - Aug 2011

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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