Comparison of day 3 FSH serum values as determined by six different immunoassays

BACKGROUND: The accurate assessment of FSH concentration is important for evaluating ovarian function prior to IVF. However, a number of different assay techniques are currently in use, leading to inconsistencies in the hormone data being reported. To address this problem, we measured FSH concentration using a number of commercially available systems. METHODS: Day 3 serum FSH levels were measured in 215 healthy fertile women using six different immunoassays: Coatria (125)I (Bio-Mérieux), ACS-180 (Bayer Diagnostics), Advia-Centaur (Bayer Diagnostics), Vitros ECi (Ortho-Clinical Diagnostics), Architect i2000 (Abbott) and Elecsys 2010 (Roche Diagnostics). RESULTS: According to the immunoassay, means +/- SD of FSH concentrations were: 6.5 +/- 2.2 mIU/ml for Coatria (125)I, 6.8 +/- 2.7 mIU/ml for Advia-Centaur, 6.7 +/- 3.0 mIU/ml for Vitros ECi, 7.6 +/- 3.0 mIU/ml for ACS-180, 8.2 +/- 3.3 mIU/ml for Architect i2000 and 8.8 +/- 3.0 mIU/ml for Elecsys 2010. CONCLUSION: Day 3 FSH values determined by six different immunoassays were significantly different (P < 0.01, paired t-test). Physicians must take care when interpreting results from different clinical laboratories.