RESUMO
INTRODUCTION: Charcoal- or resin-stripping of fetal bovine serum (FBS) or bovine calf serum (BCS) intended for supplementation of cell culture media is widely practiced to remove a variety of endogenous compounds, including steroid, peptide, and thyroid hormones. The possibility that stripping removes other biologically relevant factors from serum may not be appreciated. METHODS: In this report, standardized clinical laboratory testing methods were used to assess the effects of resin- and charcoal-stripping on content in FBS and BCS of more than 25 analytes in the sera. RESULTS AND CONCLUSION: In addition to hormones, the serum constituents affected by stripping are certain vitamins, electrolytes, enzyme activities, and metabolites.
Assuntos
Carvão Vegetal/farmacologia , Meios de Cultura , Resinas Sintéticas/farmacologia , Soro/efeitos dos fármacos , Animais , Bovinos , Técnicas de Cultura de Células/métodos , Técnicas de Cultura de Células/normas , Meios de Cultura/química , Meios de Cultura/normas , Eletrólitos/análise , Eletrólitos/isolamento & purificação , Ativadores de Enzimas/análise , Ativadores de Enzimas/isolamento & purificação , Enzimas/análise , Enzimas/metabolismo , Hormônios/análise , Hormônios/isolamento & purificação , Soro/química , Vitaminas/análise , Vitaminas/isolamento & purificaçãoRESUMO
BACKGROUND: Accurate measurement of estradiol is important in clinical settings. The quality of laboratory estimations of estradiol may be assessed through external quality-assurance surveys. METHODS: Estradiol was measured by microparticle enzyme immunoassay (MEIA) and other immunoassays. Proficiency testing of medical laboratories was conducted using samples prepared from normal male human serum supplemented with exogenous estradiol and other steroid and nonsteroid hormones, and participant laboratories measured estradiol by a variety of commonly used immunoassay techniques. RESULTS: The imprecision (CV) for measurement of estradiol [100-300 ng/L (367-1102 pmol/L)] was 1.5 microg/L (>5.2 nmol/L) interfered with the MEIA method, leading to decreased recovery of added estradiol by up to 50%. This suppression in estradiol measurement was prevented by dilution of the specimen before measurement. Addition of unconjugated estriol gave a positive bias in some other immunoassay methods for estradiol. Poor comparability among the immunoassay methods for measurement of estradiol at clinically relevant concentrations [ approximately 60 ng/L (220 pmol/L)] was revealed. CONCLUSIONS: A negative interference of unconjugated estriol with the MEIA method is a source of error for estradiol measurement. Lack of specificity and lack of comparability among immunoassay methods for estradiol may have detrimental effects on medical practice.