Diagnostic utility of colourimetric readout loop-mediated isothermal amplification assay for rapid detection of Babesia gibsoni at the clinical point-of-care (POC)

Rapid molecular detection of Babesia gibsoni is needed in veterinary settings where conventional polymerase chain reaction (PCR) is limited by equipment requirements, technical complexity and turnaround time. We developed a closed-tube, colourimetric loop-mediated isothermal amplification (LAMP) assay targeting the 18 S rRNA gene of B. gibsoni and integrated the assay with a palm-sized portable incubator. Using quantified B. gibsoni DNA, the assay achieved the limit of detection (LoD) of 100 copies/reaction, matching that of an ITS-based TaqMan qPCR comparator, with visual results after 20 min of amplification. Diagnostic performance was assessed using DNA extracted from 200 archived canine blood samples submitted for suspected tick-borne infection. Compared with qPCR, the portable LAMP assay detected all 41 qPCR-positive and all 159 qPCR-negative samples, yielding 100% sensitivity (95% CI: 91.4–100%), 100% specificity (95% CI: 97.7–100%) and 100% overall accuracy/agreement. Inter-reader agreement for visual interpretation was also complete. This portable colourimetric LAMP platform provides a technically simple molecular assay for targeted detection of B. gibsoni using extracted canine blood DNA and warrants further evaluation in prospective near-patient workflows.