Method requirements The most reliable biomarker measurements

3.3.7. Method requirements
The most reliable biomarker measurements are obtained using instrumentation that can unambiguously identify and quantify the analyte of interest. The state-of-the-science instrument for measuring BPA is high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) (Ye et al., 2005); all seven publications used this methodology. Thus, all received a Tier 1 'SNG-1153' categorization. Although reviewers raised no issues regarding application of this SNG-1153 in the current assessment, we recommend that this be revisited using biomarkers measured using differing analytical methods.