Examination of Proposed Manufacturing Standards Using Low Template DNA

Part # PS193


Kara Raymond, Jennifer Setlak, Charles Stollberg, Susan Wigdal, Douglas Storts and Kristina Pearson Promega Corporation, 2800 Woods Hollow Road, Madison, WI 53711, USA

Forensic DNA laboratories rely on reagent and plastics manufacturers to supply high-quality products with minimal interference from contaminating DNA. With the increasing sensitivity of short tandem repeat (STR) amplification systems, levels of DNA that were previously undetected may now generate partial profiles. To address the concern of laboratories worldwide, accrediting bodies in the United Kingdom and Australia proposed guidelines, PAS377 and AS5483, respectively. As a result of these initiatives, a new international ISO standard has been drafted. ISO18385 will be an internationally applicable ISO standard for forensic consumable manufacturers if/when approved. Therefore, as a manufacturer, we need to understand the limit of detection for the analysis methods currently being used and what level of contaminating DNA would interfere with analysis in customer labs.
To determine the sensitivity of STR analysis, we analyzed the sensitivity of its two major components: the capillary electrophoresis (CE) instrument and the STR reagents.
Next, we explored proposed definitions for Forensic Grade certification. Detection at both a single cell and a single allele peak were achieved and compared to levels of contamination that would interfere in forensic laboratories.
Finally, we compared sensitivity of STR analysis to qPCR analysis. PAS377 only allows manufacturers to analyze reagents and consumables via STR analysis while ISO 18385 allows for both. The utility of both methods is discussed.

Printed in USA.