OBJECTIVETo develop a rapid, highly sensitive, and quantitative method for the detection of NT-proBNP levels based on a near-infrared point-of-care diagnostic (POCT) device with wide scope.

METHODSThe lateral flow assay (LFA) strip of NT-proBNP was first prepared to achieve rapid detection. Then, the antibody pairs for NT-proBNP were screened and labeled with the near-infrared fluorescent dye Dylight-800. The capture antibody was fixed on a nitrocellulose membrane by a scribing device. Serial dilutions of serum samples were prepared using NT-proBNP-free serum series. The prepared test strips, combined with a near-infrared POCT device, were validated by known concentrations of clinical samples. The POCT device gave the output of the ratio of the intensity of the fluorescence signal of the detection line to that of the quality control line. The relationship between the ratio value and the concentration of the specimen was plotted as a work curve. The results of 62 clinical specimens obtained from our method were compared in parallel with those obtained from the Roche E411 kit.

RESULTSBased on the log-log plot, the new method demonstrated that there was a good linear relationship between the ratio value and NT-proBNP concentrations ranging from 20 pg/mL to 10 ng/mL. The results of the 62 clinical specimens measured by our method showed a good linear correlation with those measured by the Roche E411 kit.

CONCLUSIONThe new LFA detection method of NT-proBNP levels based on the near-infrared POCT device was rapid and highly sensitive with wide scope and was thus suitable for rapid and early clinical diagnosis of cardiac impairment.