Study question: Are the new Ansh Labs Ultra-Sensitive anti-Müllerian hormone (AMH) and picoAMH ELISA assays suitable for clinical use and is the Ultra-Sensitive assay comparable to the Beckman Coulter AMH Gen II assay?
Summary answer: The Ultra-Sensitive assay appears to have different calibration to the Gen II assay, but has performance characteristics generally suitable for clinical use.
What is known already: The Gen II assay is the most commonly used AMH assay in routine biochemistry at present, but persistent calibration/interference problems have been reported.
Study design, size, duration: Serum from patients referred for AMH measurement was assayed (in duplicate) using the Gen II assay in Glasgow Royal Infirmary between January and February 2013. We randomly selected 193 stored serum samples to re-run (in duplicate) using the Ultra-Sensitive AMH Ansh Labs assay, blinded to the original result. Samples that returned low results were run on the picoAMH Ansh Labs assay. Performance characteristics and linearity of the new assays were also assessed.
Participants/materials, setting, methods: All serum samples from patients referred for AMH at Glasgow Royal Infirmary between January and February 2013 were eligible for inclusion. Investigators were blinded to any identifiable information regarding the patients, including sex, age and reason for AMH measurement.
Main results and the role of chance: Intra-assay and inter-assay coefficients of variation of the Ultra-Sensitive and picoAMH assays were ≤6.0 and ≤10.7%, respectively, over a range of concentrations. The assays had mean linearity of 98 and 97% over the dilution range of 1:2-1:16 and 1:2-1:8, respectively. The limit of detection of the ultrasensitive assay was calculated to be 0.34 pmol/l. For 166 samples which provided a quantitative result on the Gen II and Ultra-Sensitive Ansh Labs assays, the median (interquartile range) was 12.2 (3.4-29.3) pmol/l and 20.0 (6.6-36.8) pmol/l, respectively (P<0.0001). The Passing-Bablok regression equation (in pmol/l) was y (Ultra-Sensitive) = 1.7 + 1.4 × Gen II. More samples were below the clinical cut-off of 5.4 pmol/l using the Gen II assay (a difference between paired proportions of 15.0%, P < 0.001). Fifteen of the 22 undetectable samples yielded a measurable concentration result on the picoAMH assay.
Limitations, reasons for caution: The present study is a pragmatic assessment of the new assay under ideal conditions. Lot-to-lot variation could not be assessed. Demographics and outcomes of patients referred for AMH measurement were not known.
Wider implications of the findings: The Ansh Labs Ultra-Sensitive assay performance characteristics are similar to the Gen II assay and may be suitable for clinical and epidemiological use. Enhanced sensitivity of the Ansh Labs picoAMH assay enables measurement of low AMH concentrations. These results re-emphasize the need for an AMH international standard.
Study funding/competing interest(s): Ansh Labs provided kits for this study free of charge. The manufacturer played no part in conducting assays or data analysis. S.M.N. has received speaker's fees and participated in advisory boards for Beckman Coulter, Merck Serono, MSD and Ferring regarding AMH. P.W. is supported by British Heart Foundation fellowship FS/12/62/29889. We declare no other financial relationship or competing interests.
Keywords: AMH; anti-Mullerian hormone; immunoassay; ovarian reserve; validation studies.