A LAMP-Assay for the Detection and Genotyping of HPV Causing Plantar Warts From Skin Scrapes Samples

HPV diagnosis of plantar warts can be challenging to health professionals, while treatment outcomes depend on the HPV genotype. PCR based diagnostics are useful; however, LAMP may work better. In this study, we developed a LAMP assay and compared it to conventional PCR. Moreover, we tested its use on skin scrapes without DNA purification. Results showed a very good agreement between the LAMP assay and the PCR method (Kappa, κ = 0.842). The LAMP assay had a lower detection limit (C95: 2.46 × 10³ copies/µL) compared to the PCR (C95: 1.51 × 10⁴ copies/µL). Viral load measurement by qPCR revealed statistically significant differences across HPV genotypes. Many viral loads were at 10³ copies/µL, below the detection limits of most standard HPV PCR methods. Skin scrapes could be used as target for the LAMP assay; however, optimization is required to improve the lower detection limit. The LAMP assay performed better at detecting and genotyping HPV than PCR and sequencing based methods. LAMP was able to resolve and detect multi-genotype infections. Our results suggest that LAMP is useful for diagnosing HPV in plantar warts, by reducing costs, time and need of specialized equipment, thereby lending itself to use as a promising and rapid point-of-care testing in clinical practice.