Multiplex_QA: An exploratory quality assessment tool for multiplexed electrophoretic assays

Abstract

Multiplex_QA is a data analysis tool for visualizing short- and long-term changes in the performance of multiplexed electrophoretic assays, particularly the commercial short tandem repeat (STR) kits used by the human forensic identity community. A number of quality metrics are calculated from the signal collected for the internal size standard included in nearly all multiplex assays. These quality metrics are related to the signal intensity, symmetry, retention, resolution, and noise of data collected by capillary electrophoresis systems. Interlocking graphical displays enable the identification of changes in the quality metrics with time, evaluation of relationships among the metrics, and detailed examination of electropherographic features of particularly interesting analyses. While primarily intended for exploring which metrics are most useful for documenting data quality, the current version of the tool is sufficiently robust for use by forensic scientists with an interest in data analysis and access to a fast desktop computer.

Suspension bead array branch migration displacement assay for rapid STR analysis

“…The electrophoretic profiles are analyzed by software that determines the STR allele sizes [4,5]. With the completion of the human genome sequence, additional markers have been characterized, currently encompassing around one million STR loci.…”

Forensic Science

“…Using computer-generated conceptual mixtures, it was noted that based solely on the number of observed alleles, approximately 3% of three-person mixtures would possess a maximum of four alleles across all 13 STRs examined and could be mischaracterized as two-person mixtures (163). A new software tool for assessing quality of electrophoretic data from multiplex STR assays named Multiplex_QA was described (164) and is freely available for download from http:// www.cstl.nist.gov/biotech/strbase/software.htm.…”