[HPLC, RIA, FPIA. Evaluation of 3 methods for the assay of vancomycin].

We describe a rapid and accurate high performance liquid chromatographic (HPLC) method for vancomycin quantitation. This method is then compared with two immunoassays, RIA and FPIA. The chemical extraction step needed for HPLC is simple and rapid. Both conventional reversed phase HPLC and high speed reversed phase HPLC were tested. The mobile phase was a mixture of aqueous ammonium acetate and acetonitrile. Specificity of the HPLC assay was good. Serum levels in 112 clinical specimens assayed by HPLC were regressed against the levels obtained for the same samples by both RIA and FPIA. The correlation was good (RIA : r = 0.945; FPIA : r = 0.967). Considering the disadvantages of RIA, HPLC and FPIA emerge as the methods of choice.