NCJ Number
229266
Journal
Journal of Forensic Sciences Volume: 54 Issue: 6 Dated: November 2009 Pages: 1278-1286
Date Published
November 2009
Length
9 pages
Annotation
A series of experiments were conducted in order to examine the effect of the chemistries of Hemastix - a reagent strip commonly used by police investigators and forensic laboratories as a screening test for blood - on the Promega DNA IQTM system as a DNA extraction method.
Abstract
The experiments performed found that one or more chemicals embedded in the Hemastix reagent strip severely impaired the ability to recover DNA when used in conjunction with the Promega DNA IQTM system. Although the exact mechanism of this interference was not identified, the authors suspect that the reporting dye, TMB, played a significant role in preventing DNA from binding to the magnetic beads. In addition, the experiments also showed that the interactions of the chemical components to the magnetic beads are irreversible, since the chemical cannot be washed from the compromised magnetic beads. Chemistries of the Hemastix do not interfere in any way with DNA extraction performed using phenol-chloroform. Blood, saliva, buccal swabs, scalp hair, urine, and clothing used as the sources of contact DNA used in these experiements were contributed by volunteers from the laboratory personnel. The descriptions of materials and methods address samples, the Hemastix test, automated protocols, DNA extraction, DNA quantification, PCR amplification, capillary electrophoresis, manual processing of samples, and the setup for the seven experiments. Several experiments investigated the adverse effect of Hemastix on DNA recovery by the DNA IQTM, all of which were designed to examine the adverse effects of Hemastix on DNA recovery by the DNA IQTM system. Other experiments specifically addressed the nature of the interference. 7 tables and 20 references