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SpermX Outperforms Traditional DNA Extraction Methods

Written by: Alan Baker 23rd February, 2024

Crime laboratories have faced backlogs of unanalysed sexual assault kits (SAKs) for decades. While laboratories have spent considerable effort to combat these backlogs, an often-overlooked issue is the low success rate of obtaining informative DNA profiles of perpetrators when testing these kits.

The National Institute of Justice has indicated that the current procedures for analysing sexual assault samples exhibit a high failure rate, with 60% to 80% of the kits tested failing to generate viable profiles.

Furthermore, even when samples are positive for male DNA, 34% of SAKs do not result in the retrieval of male D N A following differential extraction. A recovery rate of less than 30% for available sperm DNA is a contributing factor to this low effectiveness.

The SpermX™ technique (SX) has demonstrated an ability to recover over 80% of sperm DNA from samples related to sexual assault.

Researchers conducted a cross-laboratory comparison between the SX method and conventional differential extraction (DE) methods. They processed mock samples, which contained known proportions of female epithelial cells to sperm cells, using both techniques.

The findings showed that SX consistently produced DNA profiles suitable for CODIS submission, even from samples containing as few as 25 sperm cells, in contrast to DE, which often failed to yield usable results. On average, SX achieved a seven-fold increase in the recovery of distinct male alleles compared to DE.

In summary, SX surpassed DE in retrieving greater amounts of male DNA with minimal contamination from female cells in samples typical of sexual assault, significantly enhancing the success rate in obtaining usable DNA profiles to assist in resolving cases of sexual assault.