# Evaluation of a novel PCR-based assay for the detection of Candida auris colonization

## TL;DR

This study evaluates a new PCR test for detecting Candida auris colonization, showing it performs well compared to traditional methods and lab-developed tests.

## Contribution

This is the first evaluation of the FDA-approved Diasorin Simplexa C. auris assay outside of the FDA submission process.

## Key findings

- The assay demonstrated 100% sensitivity and 90% specificity compared to culture.
- It showed 100% agreement with two existing lab-developed tests.
- The assay had 100% analytical specificity and no cross-reactivity.

## Abstract

Candida auris is an emerging fungal pathogen linked to healthcare-associated infections, necessitating rapid and accurate detection for effective infection control. This study evaluated the analytical and clinical performance of the Diasorin Simplexa C. auris Direct IVD assay compared to traditional culture as the reference standard and also to two lab-developed tests (LDTs) already validated in our laboratory: one using DSQ Alert primers/probes on the Roche Cobas 5800 and another on the DiaSorin LIAISON MDX platform. Clinical accuracy was assessed using deidentified residual axillary/groin surveillance specimens from 20 culture-positive and 20 culture-negative patients. Analytical specificity was tested against 14 microbial species commonly found in the axilla/groin. Analytical sensitivity was determined using ZeptoMetrix C. auris strain Z485. Specimen stability was examined at various temperatures. Environmental swabbing was also conducted before and after sample handling. The Diasorin Simplexa C. auris IVD assay demonstrated 100% sensitivity and 90% specificity relative to culture and showed 100% positive agreement with both LDTs and 100% negative percent agreement with the DSQ Alert LDT. The assay also achieved 100% analytical specificity, with no cross-reactivity observed, and an analytical sensitivity of 702 CFU/mL. Specimen integrity remained stable for up to 30 days under all storage conditions. No environmental contamination was detected. The DiaSorin Simplexa C. auris IVD assay demonstrated strong analytical and clinical performance while offering advantages in speed, ease of use, and flexible batch size. It may serve as a practical solution for institutions seeking timely C. auris screening in support of infection prevention protocols.

Candida auris is an important yeast notable for its ability to easily colonize people as well as its drug resistance. Colonized patients who become immunocompromised may ultimately become infected with C. auris, without many options for treatment. Many health care facilities mandate screening patients for colonization with this yeast to help prevent transmission. This work evaluates the recently FDA approved Diasorin Simplexa C. auris PCR based screening assay and compares its performance to cultures, as well as two existing lab-developed assays. It is the first assay performance evaluation outside of the FDA submission.