MEASUREMENT OF ANTIMICROBIAL AGENTS IN CEREBROSPINAL-FLUID USING THE ABBOTT TDX ANALYZER

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 meningi tis. We evaluated CSF as a specimen type for the measurement of amikac in, gentamicin, tobramycin, and vancomycin on the Abbott TDx analyzer. Coefficients of variation for CSF spiked with these antimicrobial age nts 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 var ious levels with equal amounts of the antibiotics. Correlation coeffic ients for serum vs. CSF for these agents were 0.999. Recoveries ranged from 86% to 134%. Sensitivity for these assays is about fourfold bett er for CSF than for serum. CSF appears to be an acceptable specimen ty pe for the measurement of these antibiotics using the Abbott TDx analy zer. (C) 1993 Wiley-Liss, Inc.