Instability of standard calibrators may be involved in overestimating vancomycin concentrations determined by fluorescence polarization immunoassay.
Ther Drug Monit
; 18(1): 80-5, 1996 Feb.
Article
em En
| MEDLINE
| ID: mdl-8848826
ABSTRACT
Fluorescence polarization immunoassay (FPIA) is widely used to determine serum vancomycin concentrations, and it has been shown to over-estimate vancomycin concentrations in sera from renally impaired patients. This phenomenon has generally been thought to result from interference by vancomycin crystalline degradation products (CDP-1). In this study, we confirmed that serum vancomycin concentrations in various patients determined by FPIA were higher than those determined by high-performance liquid chromatography (HPLC) or enzyme multiplied immunoassay (EMIT). However, the quantitative differences in the serum vancomycin concentrations determined by FPIA versus HPLC were higher than the CDP-1 concentrations, even when the cross-reactivity of FPIA to CDP-1 is assumed to be 100%. When the vancomycin calibrators for FPIA were stored at 4 degrees C for 30 days, their concentrations determined by FPIA and HPLC decreased by 14 and 20%, respectively, and CDP-1 corresponding to 20% of primary vancomycin was formed. When stored at 25 degrees C, the degradation of vancomycin was more marked. We concluded that not only the cross-reactivity of FPIA to CDP-1 but also the instability of calibrators may cause the overestimation of serum vancomycin concentrations determined by FPIA.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vancomicina
Limite:
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Ther Drug Monit
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Japão