Teicoplanin measurement in patients with renal failure: comparison of fluorescence polarization immunoassay, microbiological assay, and high-performance liquid chromatographic assay.

Characterization of antibiotic pharmacokinetics in patients with renal insufficiency may be complicated by interfering substances within the assay. We compared three different assays for teicoplanin in serum and dialysate of 10 hemodialysis and six continuous ambulatory peritoneal dialysis (CAPD) patients. The microbiological assay (micro) had a within-run and between-run coefficient of variation (% CV) of less than 7.5% for concentrations ranging from 0.2 to 96 micrograms/ml. The high-performance liquid chromatographic assay (HPLC) within- and between-run %CV was less than 8% for concentrations ranging from 1 to 80 micrograms/ml. The fluorescence polarization immunoassay (FPIA) within- and between-run %CV was less than 7% for concentrations ranging from 5 to 100 micrograms/ml. In serum of hemodialysis patients FPIA results were slightly higher than HPLC results: FPIA = 1.11 HPLC + 2.37 (r = 0.975, n = 202), and FPIA concentrations in serum were also slightly higher than those measured by micro (FPIA = 1.21 micro - 1.57, r = 0.972, n = 161). The HPLC and micro serum results were also comparable in hemodialysis patients: micro = 0.92 HPLC + 2.89, r = 0.953, n = 160. However, in CAPD patients micro results were lower than HPLC results in serum (micro = 0.82 HPLC + 0.49, r = 0.981, n = 262). In peritoneal dialysate, HPLC values were approximately 60% of the micro values. Thus, FPIA may be the optimal technique for therapeutic monitoring of teicoplanin in the clinical setting due to its simplicity, specificity, and good correlation to HPLC and micro.