A multicentre evaluation of the Elecsys® anti-Müllerian hormone immunoassay for prediction of antral follicle count.

RESEARCH QUESTION: What concentration of anti-Müllerian hormone (AMH) corresponds to an antral follicle count (AFC) >15 for determination of ovarian reserve? DESIGN: A prospective study conducted at 13 US fertility clinics in women aged 21-44 years who presented for AFC evaluation by transvaginal ultrasound. Serum samples were collected at the time of AFC evaluation (menstrual cycle day 2-4). AMH concentrations were measured by the Elecsys® AMH immunoassay; oestradiol and follicle-stimulating hormone (FSH) concentrations were also measured. The serum AMH cut-off able to detect AFC >15 with high sensitivity was determined (derivation cohort). Clinical performance of the AMH assay at the derived cut-off was evaluated (validation cohort). Receiver operating characteristic (ROC) analyses were also performed. RESULTS: In the derivation cohort (n = 306), an optimal serum AMH cut-off value of 1.77 ng/ml was determined to correspond to AFC >15 with 89.63% sensitivity and 69.01% specificity, using the Elecsys AMH assay. In the validation cohort (n = 856), this 1.77 ng/ml cut-off could identify women with an AFC >15 with a sensitivity of 88.34% and a specificity of 68.29%; corresponding positive predictive and negative predictive values were 75.19% and 84.34%, respectively. ROC analyses demonstrated that AMH performed better than oestradiol or FSH in predicting AFC, with area under the curves of 85.7%, 57.1% and 69.7%, respectively, in the validation cohort. CONCLUSION: The Elecsys AMH immunoassay provides a robust and fully automated method to measure serum AMH levels. Women with AMH values below the cut-off of 1.77 ng/ml are unlikely to have AFC >15.

Spectral image analysis for the absorption bands of the beta-methallyl free radical in the vapor phase.

The radicals formed in the flash photolysis of 2-methylbut-1-ene and subsequent reactions have been investigated by kinetic spectroscopy and gas liquid chromatography. Less than 10% of photo products are formed by a molecular made of fission of the excited olefin, and of the radical modes the relative probabilities of band fission, beta(CH):beta(CH):alpha(CC) are 13:1.37:1. The extinction coefficients of beta-methallyl radical measured experimentally for all the absorption bands. The decay of the beta-methallyl radical was second order. The rate constant for the beta-methallyl radical recombination experimentally measured was 2.6+/-0.3 x 10(10) l mol(-1)s(-1) at 295+/-2K. The spectrum image showing the absorption bands was examined by image processing techniques in order to improve the visual experience of each band by localizing to a specific region of interest. Experimental results illustrate how the exact location of absorption bands was clearly extracted from the spectral image and further improvements in the visual detection of absorption bands.

Stokes and anti-Stokes Raman scattering of 5H-dibenzo(a,d)cyclohepten-5-ol.

The ultraviolet absorption and emissions as well as Stokes and anti-Stokes Raman scatterings of spectroscopically pure 5H-dibenzo(a,d)cycloheptene-5-ol were investigated by flash and laser-flash photolysis technique in solution at room temperature and at 77K. The whole spectrum, absorption, excitation, prompt and delayed fluorescence, T-T absorption spectra were recorded photographically and photoelectrically in the ultraviolet and visible region and phosphorescence spectrum, Stokes, anti-Stokes scatterings were recorded at 77K.