# Performance of the LIAISON PLEX yeast blood culture assay for identifying 16 invasive fungal pathogens in blood cultures

## TL;DR

A new blood culture assay rapidly and accurately identifies 16 invasive fungal pathogens in bloodstream infections, improving treatment speed and accuracy.

## Contribution

The LIAISON PLEX Yeast Blood Culture assay demonstrates high sensitivity and specificity for detecting 16 fungal pathogens in blood cultures.

## Key findings

- The assay achieved 100% detection of target fungal pathogens and 0% false positives in negative blood cultures.
- It showed 100% reproducibility within and across sites, with high sensitivity and specificity in both clinical and contrived samples.
- The assay detected low concentrations of fungi even in the presence of high concentrations of confounding organisms.

## Abstract

Fungi frequently cause potentially life-threatening bloodstream infections, particularly in immunocompromised and hospitalized individuals. Molecular methods can allow earlier pathogen identification for faster optimization of appropriate therapy. This multisite study evaluated the analytical and clinical performance of the automated multiplex LIAISON PLEX Yeast Blood Culture nucleic acid assay (Luminex Corporation, Northbrook, IL), which detects and identifies 14 Candida and 2 Cryptococcus pathogens from positive blood cultures. Samples included 69 prospectively collected specimens, 63 pre-selected samples, and 829 contrived specimens. The assay demonstrated 100% positivity in detecting target fungal pathogens and 0% positivity in negative blood cultures. All 13 tested bottle/matrix types gave 100% detection of six evaluated pathogens. Limits of detection ranged from 7.77 × 102 CFU/mL (Candida famata) to 2.83 × 105 CFU/mL (Candida albicans). The assay identified five strains tested for each of the 16 target species, indicating good inclusivity. No cross-reactivity occurred with 40 bacterial strains. Cross-reactivity with 2 of 37 off-target fungi (Candida [Yarrowia] deformans and Candida pseudohaemulonii) was predicted by in silico sequence analyses. Low concentrations of on-panel fungi were detectable alongside high concentrations of potential fungal and bacterial confounders. Reproducibility was 100% within-lab and 99.7% across sites. For combined prospective plus pre-selected specimens, sensitivity/positive percent agreement (PPA) was 100% for detected fungal pathogens, and specificity/negative percent agreement (NPA) was 97.6%‒100.0%. Common pathogens in prospective samples were Candida glabrata (36%) and C. albicans (25%). Contrived specimen PPA was 100%, and NPA was ≥99.6%. The LIAISON PLEX Yeast Blood Culture assay provides outstanding sensitivity and specificity for rapidly identifying and differentiating fungal pathogens in positive blood culture specimens.

Bloodstream fungal infections have serious risks of illness and death. Optimal treatment requires early pathogen identification so appropriate antifungal therapy can be immediately started. Blood culture is standard for confirming fungal infection but takes several days for results and may not provide detailed pathogen information. The LIAISON PLEX Yeast Blood Culture assay quickly analyzes fungus-positive blood cultures to identify 16 pathogenic fungi, including multiple Candida spp. that are common causes of bloodstream infection. This study demonstrated a high degree of test accuracy and reliability in rapidly identifying the infective pathogen in blood cultures from 132 patients with demonstrated culture-positive fungal infections. Assay performance was confirmed in 829 contrived samples, whereby samples were spiked with different fungal pathogens.