Alan Rodriguez, SHENG NI

FLASH Diagnostics Limited, HONG KONG, Hong Kong

Objectives

To evaluate the clinical performance and practical utility of in-clinic isothermal molecular assays for the detection of five common feline respiratory pathogens, using quantitative PCR as the reference standard.

Methods

A prospective diagnostic evaluation was conducted using nasal, oropharyngeal, and conjunctival swab samples collected from cats presenting with respiratory signs at multiple veterinary clinics in Hong Kong. More than 150 clinical samples were included in the analysis.

Samples were tested in-clinic by nurses or technicians during the consultation. The assay incorporates a disposable sample preparation cartridge followed by isothermal amplification and qualitative detection via lateral flow strip readout. The tests target pathogen-specific nucleic acid sequences for feline herpesvirus type 1, feline calicivirus, Bordetella bronchiseptica, Mycoplasma felis, and Chlamydia felis.

All samples were also analysed using laboratory quantitative PCR assays. Diagnostic sensitivity, specificity, and overall agreement were calculated relative to the PCR reference method.

Results

Analysis of more than 150 clinical samples demonstrated diagnostic sensitivities and specificities above 90% for all five pathogens compared with reference quantitative PCR, with overall agreement exceeding 90% across targets.

Analytical sensitivity studies showed limits of detection as low as 500 copies per reaction for selected assays. The tests detected positive samples with PCR cycle threshold values up to 37 and maintained consistent performance across samples spanning a broad cycle threshold range (20–37). No cross-reactivity was observed among the evaluated pathogens.

The total time to result was approximately 35 minutes from sample addition, with approximately 4 minutes of hands-on time in a real practice scenario.

Statement: Impact/ Clinical Significance

Rapid molecular detection of feline respiratory pathogens in the veterinary clinic may support earlier clinical decision-making, facilitate targeted treatment, and improve infection control in multi-cat environments such as shelters, breeding facilities, and hospitals. Point-of-care molecular diagnostics may therefore provide a practical enhancement for frontline small animal practice.