BOVINE BLOOD ANALYSIS FOR NATURAL HORMONES - AN OVERVIEW OF ANALYTICAL STRATEGIES

The results of an inquiry, organized among a large number of European Community (EC) control laboratories, revealed that most EC countries have a control program for the natural hormones 17beta-estradiol and 17beta-testosterone which is based on the analysis of samples of plasma or serum by a (radio)immunoassay procedure. The diversity within these procedures, however, is large and good quality control programs are not available. As base for such a program a method based on gas chromatography-isotope dilution mass spectrometry was developed and validated for purposes of the simultaneous accurate quantification of low levels of 17beta-estradiol and 17beta-testosterone. Accuracy, repeatability and within-laboratory reproducibility of this method are adequate. However, to obtain a limit of determination that is low enough for accurate quantification at the EC-recommended action level of 0.04 mug l-1 for 17beta-estradiol the use of negative chemical ionisation is necessary.