Measurement of antimicrobial agents in cerebrospinal fluid using the abbott TDx analyzer

Abstract

Occasionally, requests are made by our physicians for the measurement of gentamicin, tobramycin, or vancomycin in cerebrospinal fluid (CSF) specimens during the course of treating patients for bacterial meningitis. We evaluated CSF as a specimen type for the measurement of amikacin, gentamicin, tobramycin, and vancomycin on the Abbott TDx analyzer. Coefficients of variation for CSF spiked with these antimicrobial agents ranged from 0.8% to 6.5% for intra-assay values and from 2.1% to 2.3% for inter-assay values. Serum and CSF specimens were spiked at various levels with equal amounts of the antibiotics. Correlation coefficients for serum vs. CSF for these agents were 0.999. Recoveries ranged from 86% to 134%. Sensitivity for these assays is about fourfold better for CSF than for serum. CSF appears to be an acceptable specimen type for the measurement of these antibiotics using the Abbott TDx analyzer.

Development and validation of an HPLC method for vancomycin and its application to a pharmacokinetic study

“…There are also substantial differences between the coefficients of variation of both techniques, these being 9.5-12.2% and 1.5-4.1%, for RIA and FPIA, respectively [6]. Jandreski et al determined vancomycin in cerebrospinal fluid (CSF) using FPIA (TDx) and obtained correlation coefficients for serum versus CSF of 0.999, the sensitivity in these assays being four times better for CSF than for serum [7]. Morse et al demonstrated an overestimation of vancomycin concentrations on using FPIA in patients undergoing peritoneal dialysis.…”

Determination of amikacin in cerebrospinal fluid by high-performance liquid chromatography with pulsed electrochemical detection

“…The Abbott FPIA system has been shown to be suitable for the analysis of aminoglycosides in serum and other biological fluids. In the study of Jandreski and Garbincius, the FPIA TDx ® system was used for the measurement of aminoglycosides in CSF and sensitivity obtained for amikacin was 0.18 g/ml [5]. However, the disadvantage of immunoassays is the possibility of cross-reactivity between different aminoglycosides and the requirement for the suitable antibody and tracer, as well as expertise, facilities and time required to produce them.…”

Simultaneous determination of amiodarone and its metabolite desethylamiodarone by high-performance liquid chromatography with chemiluminescent detection

“…Hence, the unambiguous quantification of amiodarone and its major metabolite desethylamiodarone require a simple, specific and sensitive method that is suitable for routine analysis. Several high-performance liquid chromatography (HPLC) assays [10][11][12][13][14] as well as capillary electrophoresis [15] and micellar electrokinetic chromatography [16] methods, all of which use UV detection, have been described for the determination of amiodarone and desethylamiodarone in human plasma. The shortcoming of all of these methods is their inability in terms of specificity.…”