Fluorescent immunochromatography of vancomycin in plasma: A rapid and sensitive quantitative analysis.

Vancomycin (VAN) has a narrow therapeutic window and variable pharmacokinetic properties, which require timely monitoring of plasma concentration to adjust the dosage for better effectiveness. A sensitive and quantitative immunochromatographic method was developed to detect VAN in plasma. The linear response range of the method to detect plasma VAN was 1.25-50 µg/mL. The intra- and inter-assay coefficients were 4.68% and 8.81%, respectively, while the recovery was 89.10%-98.32%. The clinical comparative experiment results demonstrated a good correlation (r > 0.90) between the fluorescent immunochromatographic strip test and the mass spectrum. In this study, a simple, rapid, and high-sensitivity immunochromatographic method was established for detecting VAN, which helped establish the basis for further application of monitoring plasma concentration.

Comparison of Plasma Concentration of Linezolid's Detection by FICA and LC-MS/MS.

Linezolid was the first totally synthetic oxazolidinone antibiotic that was approved for clinical use against Mycobacterium tuberculosis. Our study investigated the correlation and consistency of fluorescence immunochromatography assay (FICA) and high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) in measuring linezolid levels in the plasma. Plasma samples were collected from 80 to 100 tuberculosis patients. The samples were analyzed by FICA and LC-MS/MS, and linezolid levels measured by the two methods were compared by outlier test, correlation coefficient, Bland-Altman scatter plot, Deming regression analysis and bias evaluation. A total of 83 plasma samples were collected, all of which were non-outlier. The correlation coefficient of FICA and LC-MS/MS results was 0.9845. Deming regression analysis showed that the regression equation of FICA and LC-MS/MS was y = 0.2229 + 1.0076x. The medical decision levels of 2 and 7 µg/mL were taken into the regression equation, and the 95% CI of 2- and 7-µg/mL bias were both within the allowed error range. The findings indicated a strong correlation between the results obtained from FICA and LC-MS/MS were consistent showed good correlation, demonstrating their equivalence in measurement.