Modification of the Beckman-Coulter second-generation enzyme-linked immunosorbent assay protocol improves the reliability of serum antimüllerian hormone measurement.

Objective: To determine whether the modified Beckman-Coulter 2nd-generation (Gen II) antimüllerian hormone (AMH) assay (Gen IIm) provides more consistent results following storage at room temperature and on dilution than the original Gen II assay, to compare AMH results from the modified assay with those obtained from the original assay, and to assess the relationship between new AMH values and the antral follicle count (AFC).

Design: Cohort.

Setting: Hospital fertility clinic.

Patient(s): A total of 678 consecutive women (21-46 years old) investigated for subfertility.

Intervention(s): None.

Main Outcome Measure(s): AMH was measured by means of the Gen IIm assay protocol in women with known AFC. AMH values were obtained on a subset of serum samples by means of both original and modified assays.

Result(s): Specimens analyzed by Gen IIm exhibited a proportional AMH response on dilution, and AMH values decreased by an average of 12.1% after 7 days at room temperature, in contrast to the steady increase seen with the use of the original Gen II assay. Gen IIm assay values were, on average, 51.4% higher than Gen II values. Population analysis suggested a conversion factor of 1.35 (95% CI 1.23-1.47) between the Gen IIm and historical data obtained for the Diagnostic Systems Laboratories AMH assay. The relationship between the Gen IIm AMH measurement and AFC was adequately represented by a linear function.

Conclusion(s): The Gen IIm assay gave more reliable AMH results on sample dilution and storage than the original Gen II protocol. Findings obtained with the use of the original Gen II ELISA method should be treated with caution.