Screening and Serology PPT Flashcards
Screening is the ______ and _______ of evidence for DNA analysis and or preservation
Examining and sampling
What are three ways evidence is evaluated before examining?
Ensure that the Sub form/ portal receipt is consistent with the evidence packaging and that it is consistent with the DNA Unit Evidence Submission Policy
Determine the Forensic question
Checking communications
“What is the forensic question?”
What are some things to think about in regards to finding the forensic question and how to analyze/examine the evidence?
Always “WHO” is on the evidence
But, we need to figure out “HOW do we get the WHO from the evidence” and what does it mean that the WHO was on the evidence
What do you consider when determining the order of examining evidence?
Think of the order of DNA concentration. We try to examine evidence in order of low concentration to high concentration
When do you take cuttings as opposed to a swab?
When the evidence material is porous such as a shirt and the evidence can penetrate the porous material
What are examples of stuff that you’d take a cutting from?
Clothing items for determination of the wearer, staining on fabric, cigarette butts, and adhesive on envelope
When are swabs taken as opposed to cuttings?
When evidence is non porous and or if there is expectation that biological material is on the surface of the porous material
What are examples of stuff that you’d take a swab from
Clothing for brief contact (on the exterior), plastic, metal, wood, concrete
Where do you take samples on clothing for determining the wearer?
collars, waistbands, sleeve cuffs, and interior hat bands
What is the average size of presumptive positive stains that we take through for analysis?
1.5cm2 if possible, extracted as trace
What is the size of sample that we take through for determining the wearer?
2.0cm2 extracted as Large Volume
What is our screening policy in regards to screening guns based on offenses?
P1, we take one swab from the gun and one swab from the magazine and cartridges
P2 we take one swab from the gun
What do we do in regards to multiple cartridge cases?
We group them by caliber and area of collection
In the case of cartridge cases, it is okay if there are multiple packages opened at once
We take one swab from each group of cartridges
How do we examine bulk consumable items/artifacts?
For porous items such as cigarettes, knit gloves, ski masks, and hats, we prepare a cutting to retain some of the item and take 1.5cm2 for analysis
For non porous items, take a swab of the entire item(for bottles, take swab from the mouth area)
What are things to consider when reading SAK paperwork before examining the evidence within the kit?
Any contact between the suspect and victim
If there has been any consensual sexual contact within the last 72 hours of collecting the evidence
Any changing of clothes
Time between the offense and the collection of the kit
What do we consider as intimate swabs?
Swabs from areas of penetration or near areas of penetration
What are considered non intimate swabs?
areas of potential contact on the body,
What is different in regards to the examination of intimate and non intimate swabs?
For intimate swabs, they are directly forwarded to a differential protocol
For non intimate swabs, we test each one with Acid Phosphatase. If they are POS, they are forwarded to diff protocol. If neg, all swabs for that sample are taken through a trace protocol in the case that the suspects epithelial cells are present with the victims
Describe out process for taking swabs from condoms or sex devices?
Take two swabs from each side of the condom.
For sex devices, determine the handle then take one swab from the handle and one swab from the insertion end_-> forward to basic extraction
For cases that the bulk clothing or bedding is not ALS POS, where should the item be swabbed if necessary?
For underwear, waistband and interior crotch area since a lot of cases involve digital penetration and or no ejaculation
How much of a portion is necessary to take through for tissue samples? Hair samples?
0.5cm2 for tissue 2-3cm of root end for hairs
What is serology?
The testing and identification of bodily fluids
Name some of the presumptive tests for blood
Alder test, Kastle-Meyer/PHE, Ortholidine, LMG, Tetramethylbenzidine test (TMB), Buaiacum, Aloin, Luminol, Bluestar, Fluorescein, ABA card HemaTrace, and Hemastix
