Cross-reactivity of cryptococcal antigen lateral flow assay with basidiomycetous yeasts

Area of Science:

• Mycology
• Clinical Diagnostics
• Infectious Diseases

Background:

• The cryptococcal antigen lateral flow assay (CrAg LFA) is a key diagnostic tool for cryptococcal meningitis.
• Previous reports suggest potential cross-reactivity of CrAg LFA with certain yeast species.
• The scope of this cross-reactivity within basidiomycetous yeasts remains incompletely understood.

Purpose of the Study:

• To investigate the extent of cross-reactivity of the CrAg LFA with a diverse panel of basidiomycetous yeast isolates.
• To identify specific basidiomycetous yeast species that may yield false-positive results with the CrAg LFA.

Main Methods:

• A collection of basidiomycetous yeast isolates from various genera were tested using a commercially available CrAg LFA.
• Isolates included species from genera such as Trichosporon, Naganishia, Cutaneotrichosporon, Filobasidium, and Ustilago.
• Results were analyzed to determine which species exhibited positive reactions with the assay.

Main Results:

• All tested isolates belonging to the genera Trichosporon and Naganishia showed positive reactions.
• Positive results were also observed in some isolates from the genera Cutaneotrichosporon, Filobasidium, and Ustilago.
• No cross-reactivity was noted with other tested basidiomycetous yeasts.

Conclusions:

• The CrAg LFA demonstrates cross-reactivity with multiple basidiomycetous yeast species beyond Cryptococcus.
• Clinicians should be aware of potential false-positive CrAg LFA results in the presence of these yeasts, although they rarely cause invasive infections.
• Further investigation may be warranted to understand the clinical implications of this cross-reactivity.