title: The measurement of anti-Müllerian hormone: a critical appraisal.
abstract: BACKGROUND
  Measurement of anti-Müllerian hormone (AMH) is perceived as reliable, but the literature reveals discrepancies in reported within-subject variability and between-method conversion factors. Recent studies suggest that AMH may be prone to preanalytical instability. We therefore examined the published evidence on the performance of current and historic AMH assays in terms of the assessment of sample stability, within-patient variability, and comparability of the assay methods.
  
  
  METHODS
  We reviewed studies (manuscripts or abstracts) measuring AMH, published in peer-reviewed journals between January 1, 1990, and August 1, 2013, using appropriate PubMed/Medline searches.
  
  
  RESULTS
  AMH levels in specimens left at room temperature for varying periods increased by 20% in one study and by almost 60% in another, depending on duration and the AMH assay used. Even at -20°C, increased AMH concentrations were observed. An increase over expected values of 20-30% or 57%, respectively, was observed after 2-fold dilution in two linearity-of-dilution studies, but not in others. Several studies investigating within-cycle variability of AMH reported conflicting results, although most studies suggest that variability of AMH within the menstrual cycle appears to be small. However, between-sample variability without regard to menstrual cycle as well as within-sample variation appears to be higher using the GenII AMH assay than with previous assays, a fact now conceded by the kit manufacturer. Studies comparing first-generation AMH assays with each other and with the GenII assay reported widely varying differences.
  
  
  CONCLUSIONS
  AMH may exhibit assay-specific preanalytical instability. Robust protocols for the development and validation of commercial AMH assays are required.
authors.affiliation: Department of Reproductive Medicine (O.R., C.F.), St Mary's Hospital, Central Manchester University Hospital National Health Service (NHS) Foundation Trust, Manchester Academic Health Science Centre (MAHSC), Manchester M13 0JH, United Kingdom; Department of Clinical Biochemistry (A.S., A.P.Y., P.W.P.), Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom; Centre for Biostatistics (S.A.R.), Institute of Population Health, MAHSC, University of Manchester, Manchester M13 9PL, United Kingdom; Manchester Royal Infirmary (M.K.), Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, United Kingdom; and Reproductive Medicine and Gynecology Unit (L.G.N.), GyneHealth, Manchester M3 4DN, United Kingdom.
authors.forename: Oybek
authors.initials: O
authors.lastname: Rustamov
authors.forename: Alexander
authors.initials: A
authors.lastname: Smith
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Roberts
authors.forename: Allen P
authors.initials: AP
authors.lastname: Yates
authors.forename: Cheryl
authors.initials: C
authors.lastname: Fitzgerald
authors.forename: Monica
authors.initials: M
authors.lastname: Krishnan
authors.forename: Luciano G
authors.initials: LG
authors.lastname: Nardo
authors.forename: Philip W
authors.initials: PW
authors.lastname: Pemberton
mesh_terms: D054304:Anti-Mullerian Hormone / Q000097:blood*; D001793:Blood Preservation / Q000592:standards; D001800:Blood Specimen Collection / Q000592:standards; D004797:Enzyme-Linked Immunosorbent Assay / Q000706:statistics & numerical data; D006801:Humans; D007118:Immunoassay / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D054304:Anti-Mullerian Hormone