The lateral flow immunoassay (LFIA) is one of the most successful sensing platforms for real-world point-of-care (POC) testing. However, achieving PCR-level sensitivity without compromising the inherent advantages of LFIA, such as rapid and robust operation, affordability, and naked-eye detection, has remained a primary challenge. In this study, a plasmonic scattering-utilising LFIA was proposed, created by transparentising a nitrocellulose membrane and placing a light-absorbing backing card under the membrane. This LFIA minimised the background signal from its matrix, leading to substantially enhanced sensitivity and enabling naked-eye detection of the plasmonic scattering signal from gold nanoparticles without optics. Our plasmonic scattering-utilising LFIA showed an approximately 2600–4400 times higher detection limit compared with that of commercial LFIAs in influenza A assays. In addition, it exhibited 90% sensitivity in clinical validation, approaching PCR-level sensitivity, while commercial LFIAs showed 23–30% sensitivity. The plasmonic scattering-utilising LFIA plays a ground-breaking role in POC diagnostics and significantly boosts follow-up research.

Young Eun Lee, M.S., Ha Jin Lim, M.D., Ju Heon Park, M.D., Hye Ran Kim, Ph.D., Min-Gu Kang, M.D., Ph.D., Young Kuk Cho, Ph.D., Jong Hee Shin, M.D., Ph.D., and Myung Geun Shin, M.D., Ph.D.. Ann Lab Med 2022;42:585-9. https://doi.org/10.3343/alm.2022.42.5.585

Ha Jin Lim, M.D., Hyunseok Jang, M.D., Ph.D., Naa Lee, M.D., Euisung Jeong, M.D., Yunchul Park, M.D., Younggoun Jo, M.D., Ph.D., Jungchul Kim, M.D., Ph.D., Young Eun Lee, Ph.D., Hyun-Jung Choi, M.D., Ph.D., Seung-Jung Kee, M.D., Ph.D., Jong Hee Shin, M.D., Ph.D., and Myung Geun Shin, M.D., Ph.D.. Ann Lab Med 2024;44:74-81. https://doi.org/10.3343/alm.2024.44.1.74

Mi Suk Park, Ph.D., Young Eun Lee, M.S., Hye Ran Kim, Ph.D., Jong Hee Shin, M.D., Ph.D., Hyun Wook Cho, Ph.D., Jun Hyung Lee, M.D., Ph.D., and Myung Geun Shin, M.D., Ph.D.. Ann Lab Med 2021;41:409-13. https://doi.org/10.3343/alm.2021.41.4.409

Ha Jin Lim, M.D., Jun Hyung Lee, M.D., Young Eun Lee, M.S., Hee-Jo Baek, M.D., Hoon Kook, M.D., Ju Heon Park, M.D., Seung Yeob Lee, M.D., Hyun-Woo Choi, M.D., Hyun-Jung Choi, M.D., Seung-Jung Kee, M.D., Jong Hee Shin, M.D., and Myung Geun Shin, M.D.. Ann Lab Med 2021;41:443-6. https://doi.org/10.3343/alm.2021.41.4.443

Vancomycin (VAN) is an effective antibiotic against Gram-positive bacteria and the first-line therapy to prevent and treat methicillin-resistant Staphylococcus aureus (MRSA) and severe infections. However, low concentrations of VAN can result in resistant strains. High doses of VAN can cause nephrotoxicity and ototoxicity; thus, VAN is a representative drug for which drug monitoring is recommended. Several methods have been proposed to detect VAN. Among them, lateral flow immunoassays (LFIAs) have advantages, such as simple and user-friendly operation, low sample volume requirement, and cost effectiveness. In this study, we developed an LFIA capable of rapid on-site detection such that the VAN concentration in plasma could be monitored within 20 min by a one-step detection process using whole blood without plasma separation. VAN can be detected in whole blood over a wide range of concentrations (20−10,000 ng/mL), and the LFIA reported here has a detection limit of 18 ng/mL. The applicability of the developed LFIA compared to the results of measuring VAN with a commercial enzyme-linked immunosorbent assay kit showed a satisfactory correlation (Spearman’s rho, ρ = 0.891). Therefore, the developed LFIA enables rapid and wide-range VAN detection in whole blood and can aid in drug monitoring to evaluate patients’ responses to treatment.