A homogeneous sol particle immunoassay for total oestrogens in urine and serum samples

Conjugates prepared by adsorption of antibodies to colloidal gold particles were used in a homogeneous sol particle immunoassay for total oestrogens. The assay is based on inhibition by free oestrogens in the sample of the agglutination of a reaction mixture, consisting of the sample, the gold particle anti-oestriol conjugate and a suitable amount of oestriol-16/17-monosuccinyl-bovine serum albumin. The effect of different assay conditions is discussed. Under optimum conditions for an assay performed at room temperature the measuring range for E3 in buffer was 2-10 ng/ml. After appropriate pretreatment of samples the assay can be used to quantitate the level of total oestrogens in both urine and serum. The within-run coefficient of variation was 6.3% and over-all 6.9%. This method is also suitable for the assay of other haptens.