Diagnostic Accuracy of a CRISPR-Based Assay in Smear- and Culture-Negative Fungal Keratitis.
RID-MyC assay showed 82.1% sensitivity for fungal keratitis in negative smear/culture cases.
Diagnostic Accuracy of a CRISPR-Based Assay in Smear- and Culture-Negative Fungal Keratitis.
IMPORTANCE: Diagnosing fungal keratitis (fungal keratitis) in patients with negative smear and culture results remains clinically challenging, highlighting the need for alternative diagnostic approaches.
To determine the diagnostic accuracy of the clustered regularly interspaced short palindromic repeats (clustered regularly interspaced short palindromic repeats)-based Rapid Identification of Mycoses using clustered regularly interspaced short palindromic repeats (RID-MyC) assay for detecting fungal keratitis in patients with negative smear and culture results using in vivo confocal microscopy (IVCM) as the reference standard.
DESIGN, SETTING, AND PARTICIPANTS: This prospective diagnostic accuracy study was conducted from December 2024 to March 2025 at Aravind Eye Hospital, a tertiary ophthalmology referral hospital in Coimbatore, India.
the new test correctly found fungal eye infections in most patients whose standard tests were negative
Positive predictive value was 88.5% (95% CI, 74%-95%) and negative predictive value was 66.7% (95% CI, 46%-82%).
Concordance between RID-MyC and IVCM was observed in 33 cases (80.5%).
Notably, prior antifungal treatment was most frequent (4 of 5 [80%]) among patients with positive IVCM but negative RID-MyC results.
Conversely, all patients (3 of 3 [100%]) with negative IVCM but positive RID-MyC findings had smaller, peripheral, or paracentral lesions.
In this diagnostic study, in patients with smear- and culture-negative fungal keratitis, the RID-MyC assay showed good diagnostic accuracy comparable with IVCM and was feasible in all cases, including those in whom imaging was not possible.
With its rapid turnaround and minimal equipment needs, RID-MyC may serve as a practical adjunct to conventional diagnostics, particularly in high-burden, resource-limited settings where IVCM is unavailable or contraindicated.