1 Department of Biochemistry and Hormonology and 2 Department of Obstetrics and Gynecology and Reproductive Endocrinology, Hôpital Antoine Béclère, Clamart, France
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Key words: FSH/immunoassay/menstrual cycle
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Several studies agree about the usefulness of the specific two-site enzyme-linked immunosorbent assay (ELISA) developed by Groome and O'Brien for inhibin B determination (Groome and O'Brien, 1993). The cut-off value generally used for day 3 serum inhibin B is 45 pg/ml (Seifer et al., 1997
).
Non-isotopic or isotopic immunoassays for E2 and FSH measurements are currently used in clinical laboratories and inconsistent hormone data are frequently reported, particularly for FSH, making the results difficult to interpret. These discrepancies are due to differences in methods (resulting from FSH polymorphism, antibody specificities and preparation of the standards) and result in decision limit values being different for different immunoassays.
The aim of this study was to compare FSH values obtained on day 3 of the menstrual cycle using six different immunoassays.
![]() |
Materials and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Before the clinical evaluation presented in this paper, for each method we analysed the precision (within and between runs) as described by the French National Committee for clinical laboratories (Vassault et al., 1999). It was studied using pools of serum ranging over the calibration curves. Between-run precision was analysed per 30 days using two sets of reagents.
All sera (n = 215) were evaluated by ACS-180, a multi-analyser system routinely used in our Hormonology department. For the other methods tested, the number of samples analysed was between 77 for Elecsys 2010 (these samples were also evaluated by Coatria 125I) and 133 for Vitros ECi (these samples included the 129 and 99 samples evaluated by Architect i200 and Advia-Centaur respectively). For each assay, mean and SD at day 3 were calculated. The paired Student's t-test, under Statview SE Software, was used for statistical analysis. A P-value < 0.05 was considered statistically significant.
Ethics
This study did not need approval by the French ethical committee. FSH measurements are required to evaluate the functional status of the ovaries before inclusion in an oocyte donation programme.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
For day 3 FSH measurements, concentration ranges tested, mean results and SDs for each method are presented in Table I. For each assay, the concentration ranges analysed were similar: 3.217.4 mIU/ml for Elecsys 2010, 3.115.8 mIU/ml for Coatria 125I, 3.418.4 mIU/ml for Advia-Centaur, 3.621.5 mIU/ml for Architect i2000, 2.819.8 mIU/ml for Vitros ECi and 3.420.8 mIU/ml for ACS-180. The means ranged between 6.5 (FSH Coatria 125I) and 8.8 mIU/ml (Elecsys 2010) and the SD between 2.2 (FSH Coatria 125I) and 3.3 mIU/ml (Architect i2000).
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The presence in the serum of various glycoproteins (LH, thyroid-stimulating hormone, HCG) structurally closely related to FSH (the same subunit and homologies of the ß subunits) could contribute to the observed discrepancies. However, it should be noted that all manufacturers have tested cross-reactivities against these molecules and found no significant cross-reactivity. A central part of a measuring system is the standardization of assay. Although all manufacturers have tested their standard curve calibration (`secondary standard') against the same International Standard (NIBSC, 1998
), the matrix of the standard is required to be identical to the matrix of the specimen and this condition is met only rarely [note that a FSH human recombinant standard is in preparation (Rose and Gaines-Das, 1998
), which could diminish the influence of imperfect test standardization].
The last component which explains differences in assay measurements could result from the mathematical relationship permitting, on the system used, the conversion of the signal into the concentration of hormone. In our study, we did not find a clear difference in serum FSH between assays using monoclonal antibodies or monoclonal and polyclonal antibodies. We also did not find differences according to the signal measured (isotope, direct or indirect chemiluminescence). It is likely that a combination of all these factors, involved in the immunoassay procedure, contributes to the divergence of the results obtained (Büttner, 1991). This lack of agreement between FSH immunoassays is also illustrated by the French National Quality Control which clearly shows two major and distinct populations of results (République Française, 1999
).
The present study, revealing statistically significant differences for day 3 FSH values according to the immunoassay used, raises issues for the interpretation of results from different clinical laboratories. FSH is widely used by physicians (in association with E2 and inhibin B) as a criterion for inclusion in assisted reproductive technology programmes. The discrepancies observed indicate that it is advisable to refer patients to selected laboratories using analytical methods for which they have defined reference values and decision limits for this clinical situation. We hope that, as soon as possible, manufacturers will harmonize their routine immunoassay systems. These efforts toward standardization would be beneficial for both physicians and clinical laboratories and could avoid travelling and expense for the patients.
![]() |
Notes |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Groome, N.P. and O'Brien, M. (1993) Immunoassays for inhibin and its subunits. Further applications of the synthetic peptide approach. J. Immunol. Methods, 165, 167176.[ISI][Medline]
Licciardi, F.L., Liu, H.C. and Rosenwaks, Z. (1995) Day 3 estradiol serum concentrations as prognosticators of ovarian stimulation response and pregnancy outcome in patients undergoing in vitro fertilization. Fertil. Steril., 64, 991994.[ISI][Medline]
NIBSC (1998) National Institute for Biological Standards and Controls, WHO International Laboratory for Biological Standards. Follicle stimulating hormone pituitary for bioassay. 2nd International Reference Preparation. South Mimms, Potters Bar, Herts, UK.
République Française (1999) Ministère de l'Emploi et de la Solidarité, Secrétariat d'Etat à la Santé, Agence Française de Sécurité Sanitaire des Produits de Santé. Annales du contrôle national de qualité, 16, 7879.
Rose, M.P. and Gaines-Das, R.E. (1998) Characterisation, calibration and comparison by international collaborative study of international standards for the calibration of FSH. J. Endocrinol., 158, 94114.
Scott, R.T., Toner, J.P., Muasher, S.J., Oehninger, S., Robinson, S. and Rosenwaks, Z. (1989) Follicle-stimulating hormone levels on cycle day 3 are predictive of in vitro fertilization outcome. Fertil. Steril., 51, 651654.[ISI][Medline]
Scott, R.T., Hofmann, G.E., Oehninger, S. and Muasher S.J. (1990) Intercycle variability of day 3 follicle-stimulating hormone levels and its effect on stimulation quality in in vitro fertilization. Fertil. Steril., 54, 297302.[ISI][Medline]
Seifer, D.B., Lambert-Masserlian, G., Hogan, J.W., Gardiner, A.C., Blazar, A.S. and Berk, C.A. (1997) Day 3 serum inhibin B is predictive of assisted reproductive technologies outcome. Fertil. Steril., 67, 110114.[ISI][Medline]
Sharara, F.I., Scott, R.T. Jr and Seifer, D.B. (1998) The detection of diminished ovarian reserve in infertile women. Am. J. Obstet. Gynecol., 179, 804812.[ISI][Medline]
Stanton, P.G., Robertson, D.M. and Burgon, P.G. (1992) Isolation and physicochemical characterization of human follicle-stimulating hormone isoforms. Endocrinology, 130, 28202832.[Abstract]
Vassault, A., Grafmeyer, D., de Graeve, J., Cohen, R., Beaudonnet, A. and Bienvenu, J. (1999) Analyses de biologie médicale: spécifications et normes d'acceptibitilé à l'usage de la validation de techniques. Ann. Biol. Clin., 57, 685695.[ISI]
Submitted on July 2, 2001; accepted on November 12, 2001.