Prospective study into the value of the automated Elecsys antimüllerian hormone assay for the assessment of the ovarian growing follicle pool

ObjectiveTo evaluate a new fully automated assay measuring antimüllerian hormone (AMH; Roche Elecsys) against antral follicle count in women of reproductive age.DesignProspective cohort study.SettingHospital infertility clinics and academic centers.Patient(s)Four hundred fifty-one women aged 18 to 44 years, with regular menstrual cycles.Intervention(s)None.Main Outcome Measure(s)AMH and antral follicle count (AFC) determined at a single visit on day 2–4 of the menstrual cycle.Result(s)There was a statistically significant variance in AFC but not in AMH between centers. Both AFC and AMH varied by age (overall Spearman rho −0.50 for AFC and −0.47 for AMH), but there was also significant between-center variation in the relationship between AFC and age but not for AMH. There was a strong positive correlation between AMH and AFC (overall spearman rho 0.68), which varied from 0.49 to 0.87 between centers. An agreement table using AFC cutoffs of 7 and 15 showed classification agreement in 63.2%, 56.9% and 74.5% of women for low, medium, and high groups, respectively.Conclusion(s)The novel fully automated Elecsys AMH assay shows good correlations with age and AFC in women of reproductive age, providing a reproducible measure of the growing follicle pool

der Universität Dortmund

Diagnostic assays are measurement systems, measuring the concentration of analytes in human body liquids. To ensure the stability of the measured values over time, each diagnostic assays should be standardized against a so-called master sample. This is a sample with known concentration, which is measured by a very specific and precise measurement method. From this master copies are made subsequently, such that at the end of the chain a patient sample is measured on the standardized system. A main problem for standardization systems of diagnostic assays is the definition of a master, which is stable, as analyte may be lost over time. Manufacturers of diagnostics assays as well as international organizations, especially the IFCC ∗ have recognized the need for standardization systems of diagnostic assays that ensure stability. Networks of laboratories are formed, which measure master samples with a reference measurement method and the averaged value of these measurements becomes the value of the master, the so-called assigned value. This value assignment is repeated after a certain time span for the next master sample, such that if the network is stable the continuity of master samples will be guaranteed. In the context of such laboratory networks several statistical questions arise, which are discussed and answered throughout this thesis. First it must be clear how the assigned value of the respective master and the uncertainty associated with this value is derived. The first part of the thesis examines a routine process of standardization within a laboratory network. The main sources of uncertainty within this process are revealed and how these sources have to be combined to obtain the uncertainty of the assigned value is shown. Especially the question how the uncertainty of the master is transferred to the uncertainty of the copies is discussed. A Bayesian model is presented which enables the inclusion of the uncertainty of the master within the calibration process. Based on a simulation study it is shown that thi

Statistical methods for monitoring the relationship between the IFCC reference measurement procedure for hemoglobin A(1c) and the designated comparison methods in the United States, Japan, and Sweden

BACKGROUND: The American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD)/International Diabetes Federation GDFAFCC Consensus Statement on the worldwide standardization of HbA(1c) states that"...[HbA(1c)] results are to be reported world-wide in IFCC units...and derived NGSP units...,using the IFCC-NGSP master equation." METHODS: We describe statistical methods to evaluate and monitor the relationships as expressed in master equations (MEs) between the IFCC Reference Measurement procedure (IFCC-RM) and designated comparison methods (DCMs) [US National Glycohemoglobin Standardization Program (NGSP), Japanese Diabetes Society/Japanese Society for Clinical Chemistry (JDS/JSCC), and Mono-S in Sweden]. We applied these statistics, including uncertainty calculations, to 12 studies in which networks of reference laboratories participated, operating the IFCC-RM and DCMs. RESULTS: For NGSP and Mono-S, slope, intercept, and derived percentage HbA(1c) at the therapeutic target show compliance with the respective MEs in all 12 studies. For JDS/JSCC, a slight deviation is seen in slope and derived percentage HbA(1c) in 2 of the 12 studies. Using the MEs, the uncertainty in an assigned value increases from 0.42 mmol/mol HbA(1c) (IFCC-RM) to 0.47 (NGSP), 0.49 (JDS/JSCC), and 0.51 (Mono-S). CONCLUSIONS: We describe sound statistical methods for the investigation of relations between networks of reference laboratories. Application of these statistical methods to the relationship between the JFCC-RM and DCMs in the US, Japan, and Sweden shows that they are suitable for the purpose, and the results support the applicability of the ADA/EASD/lDF/lFCC Consensus Statement on HbA1c measurement. (C) 2008 American Association for Clinical Chemistry