Multiple reaction monitoring-mass spectrometry (MRM-MS) of peptides with stable isotope-labeled internal standards (SIS) is a quantitative assay for measuring proteins in complex biological matrices. These assays can be highly precise and quantitative, but the frequent occurrence of interferences require that MRM-MS data be reviewed by an expert. The AuDIT module provides an automated method of objectively evaluating MRM-MS data to identify inaccurate transition data based on the presence of interfering signal or inconsistent recovery between replicate samples. AuDIT improves the overall accuracy of data analysis and is easily incorporated into the standard data analysis workflow.
The module implements the Automated Detection of Inaccurate and imprecise Transitions (AuDIT) algorithm developed by Abbatiello et al. (In Press). It first compares the relative product ion intensities of the analyte peptide to those of the SIS peptide and uses a t-test (in conjunction with a p-value threshold) to determine if they are significantly different. It then calculates coefficient of variation from the ratio of analyte and SIS peak areas from sample replicates, flagging transitions having excessive variation as being unsuitable.