The use of Hemastix® and the subsequent lack of DNA recovery using the Promega DNA IQTM system

• Hiron Poon ^[1] ; Jim Elliott ^[2] ; Jeff Modler ^[2] ; Chantal Frégeau ^[3]
  1. [1] Royal Canadian Mounted Police, National Forensic Services—Vancouver, Biology Services
  2. [2] Royal Canadian Mounted Police, National Forensic Services—Ottawa,Biology Services
  3. [3] Royal Canadian Mounted Police, National Services and Research

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• Localización: Journal of forensic sciences, ISSN-e 1556-4029, ISSN 0022-1198, Vol. 54, Nº. 6, 2009, págs. 1278-1286
• Idioma: inglés
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• Resumen

  • Following implementation of our automated process incorporating the Promega DNA IQTMsystem 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 usedby police investigators and forensic laboratories as a screening test for blood. Some exhibits were even tainted green following transfer of the pre-sumptive test reagents onto the samples. A series of experiments were carried out to examine the effect of the Hemastix® chemistries on the DNAIQTMsystem. Our results indicate that one or more chemicals imbedded in the Hemastix® reagent strip severely reduce the ability to recover DNAfrom any suspected stain using the DNA IQTMmagnetic bead technology. The 3,3¢,5,5¢-tetramethylbenzidine (TMB) used as the reporting dyeappears to interact with the magnetic beads to prevent DNA recovery. Hydrogen peroxide does not seem to be involved. The Hemastix® chemistriesdo not interfere in any way with DNA extraction performed using phenol-chloroform. The incompatibility of the Hemastix® chemistries on the DNAIQTMsystem forced us to adopt an indirect approach using filter paper to carry out the presumptive test