Sexual Assault Evidence Kit (SAEK) Processing
The sheer volume of sexual assault evidentiary samples submitted to forensic laboratories has compelled many laboratories to seek better solutions for processing these challenging samples. Promega offers several products that take you through each step in the sexual assault evidence kit (SAEK) workflow, from sample extraction to analysis.
The Casework Direct System, when used with the PowerQuant® System, offers an ideal workflow to screen SAEK samples. The Casework Direct System rapidly generates lysates from casework samples that may be amplified with the PowerQuant® System to screen SAEKs for male DNA and normalize human DNA templates for STR amplification with one of the PowerPlex® Systems.
View the Sexual Assault Evidence Kit (SAEK) Legislation Webinar Series On Demand
Forensic laboratories are often overwhelmed by the volume of sexual assault evidence kits (SAEKs) they receive for processing. This series of webinars, presented jointly by Promega and Bode Technology, addresses legislative issues and workflow efficiencies for SAEK processing in the US.
SAEK Processing Workflow
Choosing a Workflow
Do you go the serology route or the Direct-to-DNA route? While serology may be familiar to many forensic laboratories, a “direct-to-DNA” approach using Y screening can save time and money.
|Low throughput and labor-intensive
|High throughput; can be automated for even more efficient processing
|All samples must be processed, regardless of whether they contain male DNA
|Y screening eliminates samples that do not contain male DNA
|Limited sensitivity to detect male DNA
|High sensitivity, even with challenging samples, and improved effectiveness than what is seen with biological fluid screening for detecting male DNA from vaginal swabs, external genitalia and dried secretions
|Higher cost per sample
|Eliminating unsuitable samples and direct STR amplification of qualifying samples lower SAEK processing costs
|Poor results seen when samples are aged or improperly stored due to breakdown of enzymes used in serological screening
|A better predictor of the success of obtaining a DNA profile where enzymes that detect biological fluids may have degraded
Solutions for a Complete Workflow
Promega offers instruments, reagents and kits to support every step of the SAEK processing workflow.
|Preprocessing and Differential Extraction
|Casework Direct System
Rapidly process SAEK and trace DNA samples
|Maxwell® FSC DNA IQ™ Casework Kit
Automated benchtop DNA extraction from casework samples
Quantify autosomal and Y-chromosomal DNA and assess sample integrity
|PowerPlex® 35GY System
Amplify and detect 35 loci, including 11 Y-STR loci and the 20 CODIS core loci
Separate sperm and epithelial cells
|Maxprep™ Liquid Handler
Complete robotic system for nucleic acid purification
|Plexor® HY System
Simultaneously quantify autosomal and Y-chromosome DNA
|Spectrum CE System
A high-throughput capillary electrophoresis system for forensic and paternity labs
Why Use a Y-STR System for Your SAEK Workflow?
Y-STR analysis can provide clues in situations where autosomal STR analysis has not yielded sufficient information to help the investigation. For example, excess amounts of female DNA can often make it difficult to detect male DNA when performing autosomal STR analysis. While the autosomal loci included in the PowerPlex® 35GY System help determine the total number of contributors in mixed samples, the 11 Y-STRs help estimate the total male contributors and can detect male DNA from cases where the male perpetrator did not ejaculate, had undergone a vasectomy or where penile penetration did not occur.
Learn more about the PowerPlex® 35GY System.
SAEK Workflow Resources
Webinar: Implementing a Y-Screening/Direct-to-DNA Forensic Workflow
The Palm Beach County Sheriff's Office describes their journey through SAEK workflow development, validation and implementation.
White Paper: Stability Testing of Casework Direct Lysate
Results from studies examining long-term storage and freeze-thaw cycling of Casework Direct lysates.
White Paper: Developmental Validation of the Casework Direct Kit, Custom
Validation studies based on requirements listed in the FBI QAS and SWGDAM guidelines.