Eva Åkerlöf

Validation of radioimmunoassay for estradiol-17/3 by isotope dilution-mass spectrometry and by a test of radiochemical purity

Isotope dilution-mass spectrometry (ID-MS) was used as a reference method to determine the concentration of estradiol-17 beta (E2) in five different plasma pools (concentrations ranging from 0.040 to 65 nmol/l). The same plasma pools were also subjected to radioimmunoassay (RIA) using five different antisera of largely varying specificity. With the best antiserum (E), a direct RIA apparently gave accurate results (i.e. results statistically indistinguishable from those obtained by ID-MS) at all levels except the lowest one (0.040 nmol/l). It was shown, however, that the apparent accuracy of this RIA to some extent could be due to a lowering effect of lipids in the serum masking a lack of specificity of the antibodies. With the least specific antiserum (A), accurate results were obtained only after chromatography. However, in the assay of the lowest concentration of E2 with this antiserum there was a significant overestimation, even after chromatography. The other three antisera (B, C, D) of average quality gave accurate results in assays of plasma diethyl ether extracts in various numbers of the plasma pools tested, depending on their intrinsic specificity. This specificity was not correlated with the cross-reaction reported for individual antisera. ID-MS is difficult to use in most laboratories. We demonstrate here that the validity of a RIA may in this case be assessed by a relatively simple method, the test of radiochemical purity (RP-test). This test is based on the measurements of specific activity (e.g. dpm/pg) in small consecutive fractions of the chromatographic zone which is usually employed for the RIA.

Scheduled Intermittent Periods of in vitro Fertilization Treatments

Organization and results of an in vitro fertilization program at the Huddinge University Hospital are given from its beginning in August 1985: 6 months in advance a scheme is scheduled with 2 weeks open for treatment followed by free intervals of 3-4 weeks. Follicular development is stimulated with clomiphene citrate and hMG, and assessed by analyses of estradiol and LH in serum combined with ultrasound examinations. Following the administration of hCG, eggs are collected by transvesical aspiration guided by ultrasound. The ova are inseminated with about 50,000 motile spermatozoa, and cultured for 48 h. Up to four eggs are transferred transcervically to the uterine cavity. 158 egg pickups have been performed (August 1985 to December 1987) in 106 patients resulting in fourteen intrauterine and two ectopic pregnancies, biochemical pregnancies not counted. This protocol has restricted routine work load allowing these treatments to be part of the clinical routine. It has also allowed the application of research programs and thus optimized limited resources.

A scheduled in vitro fertilization program at Huddinge University Hospital, Karolinska Institutet, Stockholm, Sweden

embryos were transferred per patient. Twenty-four ongoing pregnancies have been established, for a pregnancy rate of 17.1%. Nine women have delivered, including two sets of twins. Of the 143 women undergoing laparoscopy for GIFT, 41 pregnancies have been established, resulting in a clinical pregnancy rate of 29%. Two ectopic pregnancies have occurred. Sixteen pregnancies have been delivered, including four sets of twins. Our 1987 pregnancy rate is 23% for IVF and 35% for GIFT. We are currently accepting 70 couples per month into our program. Embryo cryopreservation and gamete and embryo donation are options which are also available.