Evaluation of the RSID (TM)-Saliva test to detect saliva in expirated bloodstains and development of an 'in-scene' protocol
Author(s)
Thompson, Cassie
Bennett, Rebecca
Krosch, Matt N
Chaseling, Janet
Wright, Kirsty
Griffith University Author(s)
Year published
2020
Metadata
Show full item recordAbstract
The differentiation between bloodstain patterns resulting from impact events and those from the expiration of blood can be crucial to crime scene reconstruction. Physical characteristics used to distinguish impact and expirated bloodstain patterns, are often unclear or absent, making interpretation of some bloodstain patterns difficult. Presumptive tests for salivary α-amylase (SAA) exist; however, these tests are generally unsuited for use at crime scenes or have not been tested on realistic expirated bloodstains. To address this, we assessed the RSIDTM-Saliva test for detecting SAA in expirated bloodstains and developed a ...
View more >The differentiation between bloodstain patterns resulting from impact events and those from the expiration of blood can be crucial to crime scene reconstruction. Physical characteristics used to distinguish impact and expirated bloodstain patterns, are often unclear or absent, making interpretation of some bloodstain patterns difficult. Presumptive tests for salivary α-amylase (SAA) exist; however, these tests are generally unsuited for use at crime scenes or have not been tested on realistic expirated bloodstains. To address this, we assessed the RSIDTM-Saliva test for detecting SAA in expirated bloodstains and developed a modified protocol that can be used in-scene by forensic examiners. Phase 1 experiments, which involved volunteers creating simulated bloodstains by expirating volumes of their own blood onto painted timber boards, produced entirely positive results which demonstrated the test’s efficacy for realistic expirated bloodstains. Phase 2 development and evaluation of a modified in-scene protocol demonstrated that a reduced buffer volume and modified incubation could successfully detect SAA in expirated bloodstains. A significant inverse relationship was observed between the size of a bloodstain and the ‘time-to-positive’. These results support the modified RSIDTM-Saliva test protocol as a viable method to detect SAA in expirated bloodstains in a crime scene environment.
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View more >The differentiation between bloodstain patterns resulting from impact events and those from the expiration of blood can be crucial to crime scene reconstruction. Physical characteristics used to distinguish impact and expirated bloodstain patterns, are often unclear or absent, making interpretation of some bloodstain patterns difficult. Presumptive tests for salivary α-amylase (SAA) exist; however, these tests are generally unsuited for use at crime scenes or have not been tested on realistic expirated bloodstains. To address this, we assessed the RSIDTM-Saliva test for detecting SAA in expirated bloodstains and developed a modified protocol that can be used in-scene by forensic examiners. Phase 1 experiments, which involved volunteers creating simulated bloodstains by expirating volumes of their own blood onto painted timber boards, produced entirely positive results which demonstrated the test’s efficacy for realistic expirated bloodstains. Phase 2 development and evaluation of a modified in-scene protocol demonstrated that a reduced buffer volume and modified incubation could successfully detect SAA in expirated bloodstains. A significant inverse relationship was observed between the size of a bloodstain and the ‘time-to-positive’. These results support the modified RSIDTM-Saliva test protocol as a viable method to detect SAA in expirated bloodstains in a crime scene environment.
View less >
Journal Title
Australian Journal of Forensic Sciences
Note
This publication has been entered as an advanced online version in Griffith Research Online.
Subject
Biological sciences
Science & Technology
Life Sciences & Biomedicine
Medicine, Legal
Legal Medicine
Bloodstain pattern analysis