# The new gold rush in clinical diagnostics: from standard laboratory assays to fast and accurate point-of-care (POC) methods

## TL;DR

A new point-of-care diagnostic method using gold nanoparticles and amplification techniques can detect hepatitis B and C viruses quickly and accurately outside of traditional labs.

## Contribution

A novel single-tube, multiplex MCDA-AuNPs-LFB assay for HBV and HCV detection with high sensitivity and simplicity.

## Key findings

- The assay achieves analytical sensitivity comparable to lab-based PCR with faster results.
- It shows no cross-reactivity with non-target pathogens and operates under isothermal conditions.
- The method is suitable for decentralized diagnostic use due to its low cost and portability.

## Abstract

Integrating two point-of-care (POC)-amenable technologies, namely, multiple cross displacement amplification (MCDA) and gold nanoparticle-based lateral flow biosensors (AuNPs-LFB), has demonstrated excellent detection of hepatitis B virus (HBV) and hepatitis C virus (HCV). In a recent study, Zhang et al. (H. Zang, Y. Shi, Z. Wu, Q. Zhao, et al., Microbiol Spectr 13:e01738-24, 2025, https://doi.org/10.1128/spectrum.01738-24) developed a novel, single-tube, multiplex MCDA-AuNPs-LFB assay that targets the HBV S gene and the HCV 5′-UTR region. The assay operates under isothermal conditions at 64°C for 35 min, and the AuNPs-LFB assay permits a visual interpretation of results. This platform achieves an analytical sensitivity comparable to lab-based quantitative PCR but with shorter turnaround time, reduced cost, operational simplicity, and undetectable cross-reactivity to anatomically relevant, non-target pathogens, making it highly suitable for decentralized POC diagnostic applications. The success of hybrid systems in simplifying nucleic acid testing while increasing portability indicates a potential transition in clinical diagnosis from centralized tech-centered labs to local clinics, field testing, and even home care.