OBJECTIVE  To establish a carbapenemase type （KPC, NDM, OXA-48） detection method based on the combination of surface-enhanced Raman scattering （SERS） and lateral flow immunoassay （LFIA）.

METHODS  Three Au@Ag core-shell nanomaterials with Raman characteristic peaks （1 629 cm⁻¹, 1 078 cm⁻¹ and 539 cm⁻¹） were employed as SERS enhancement substrates for conjugating with monoclonal antibodies of KPC, NDM and OXA-48 to prepare the immunonano tags. The monoclonal antibodies coated at the test line （T-line） of the LFIA strip served as capture antibodies. By systematically optimizing antibody pairing method and working concentrations, a double-antibody sandwich-format SERS-LFIA detection system was established. Raman spectroscopy was utilized to analyze the characteristic peak signals at the T-line, enabling the development of a digital result interpretation method. The sensitivity, specificity, repeatability and hook effect of the detection system were systematically evaluated. By clinical sample detection, its concordance rate with polymerase chain reaction （PCR） and commercial colloidal gold kits were validated, and its diagnostic performance was evaluated.

RESULTS  A SERS-LFIA-based carbapenemase type detection method was established, which could specifically identify major enzyme types including KPC, NDM and OXA-48. The visual detection sensitivity was 5 ng/ml for all types, while the sensitivity could be improved to 1 ng/ml （for KPC and OXA-48） on the condition of Raman spectrometer. The critical concentration of hook effect was 125 ng/ml. The coefficients of variation （CV） for repeatability detection of antigens at low, medium and high concentrations were all ＜10%. With PCR detection results as the gold standard, the diagnostic sensitivity and specificity of this method were both 100.00%. The agreement rate with commercial colloidal gold detection kits was 100.00%. CONCLUSIONS The SERS-LFIA-based carbapenemase type detection method established in this study is sensitive, specific and hepeatable. It can be widely applied in clinical practice, aiming to provide a clinical diagnostic basis based on dual technical support for the prevention and control of drug-resistant bacteria.