Fungal Keratitis: Diagnostic Characteristics of the Potassium Hydroxide Preparation with Calcofluor White in Northern California

Colin Bacorn, Kieu Yen Luu, Jennifer Y. Li

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose:The incidence of fungal keratitis demonstrates significant geographic and climatic variation. We report on the characteristics of the potassium hydroxide/calcofluor white (KOH-CFW) preparation observed at a tertiary center in Northern California, a region with a low incidence of fungal keratitis.Methods:Culture-proven cases of microbial keratitis during a 5-year period were retrospectively reviewed. The sensitivity, specificity, and posttest probabilities were determined for the KOH-CFW assay. These results were compared with documented clinical impression and values reported in the literature.Results:Three hundred three of 368 episodes of microbial keratitis during the study period documented the results of a fungal culture, KOH-CFW assay, and a clinical impression. Twenty-one (6.9%) of these cultures were positive for fungal organisms. The sensitivity and specificity of the KOH-CFW test were 29% and 93%, respectively. Clinicians' initial clinical impression based solely on patients' history and examination, without the aid of any histopathologic or biochemical test results, demonstrated a sensitivity and specificity of 33% and 89%, respectively.Conclusions:The observed sensitivity and specificity of the KOH-CFW preparation are significantly lower than many previously reported values. In regions with low incidence of fungal keratitis, the KOH-CFW preparation may have diagnostic performance similar to that of the clinical impression formed only on the basis of history and physical examination.

Original languageEnglish (US)
Pages (from-to)347-352
Number of pages6
JournalCornea
Volume41
Issue number3
DOIs
StatePublished - Mar 1 2022
Externally publishedYes

Keywords

  • corneal ulcer
  • fungal keratitis
  • microbial keratitis

ASJC Scopus subject areas

  • Ophthalmology

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