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The Use of Hemastix ® and the Subsequent Lack of DNA Recovery Using the Promega DNA IQ TM System
Author(s) -
Poon Hiron,
Elliott Jim,
Modler Jeff,
Frégeau Chantal
Publication year - 2009
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2009.01173.x
Subject(s) - dna , genetics , biology
Following implementation of our automated process incorporating the Promega DNA IQ TM system as a DNA extraction method, a large number of blood‐containing exhibits failed to produce DNA. These exhibits had been tested with the Hemastix ® reagent strip, commonly used by police investigators and forensic laboratories as a screening test for blood. Some exhibits were even tainted green following transfer of the presumptive test reagents onto the samples. A series of experiments were carried out to examine the effect of the Hemastix ® chemistries on the DNA IQ TM system. Our results indicate that one or more chemicals imbedded in the Hemastix ® reagent strip severely reduce the ability to recover DNA from any suspected stain using the DNA IQ TM magnetic bead technology. The 3,3′,5,5′‐tetramethylbenzidine (TMB) used as the reporting dye appears to interact with the magnetic beads to prevent DNA recovery. Hydrogen peroxide does not seem to be involved. The Hemastix ® chemistries do not interfere in any way with DNA extraction performed using phenol‐chloroform. The incompatibility of the Hemastix ® chemistries on the DNA IQ TM system forced us to adopt an indirect approach using filter paper to carry out the presumptive test.