Contamination, Screening, Lab Technique Flashcards
what is the amended report (AR) 3125
subsection of ISO 17025 that applies directly to forensic testing laboratories
what does ANAB stand for and what does it do
- ANAB = ANSI (American National Science Institute) National Accreditation Board
- accredits the LSPCL every four years
define analytical control
a sample used to demonstrate that a method works correctly and then ensures the data is valid
explain the combined DNA index system (CODIS)
- US national DNA database that is maintained by the Federal Bureau of Investigation (FBI)
- there are twenty CODIS core STR loci required for upload of DNA profiles into the national DNA database
what is direct contamination
transfer of DNA from source of contamination to evidentiary item or sample
what is indirect contamination
transfer of DNA from the source of contamination to the evidentiary item or sample through an intermediary
what is an internal audit, how often are they performed, and who performs them
- performed by LSPCL employees who are qualified auditors
- ISO/AR internal audit: every year; LSPCL audits only follow these standards
- auditors must pass a course and competency test- FBI QAS internal audit: auditors must be a qualified DNA analyst and pass the FBI auditor course
- must meet requirements of QAS appendix C
what is an internal validation
the accumulation of test data within the laboratory to demonstrate that established methods and procedures perform as expected
what does ISO/IEC stand for and what does it do
- the acronym for the joint technical committee of the Internal Organization for Standardization and the Internal Electrotechnical Commission
- ISO/IEC develops, maintains, and promotes standards covering multiple industries
- ISO 17025: standards for testing laboratories
what is a performance check
a quality assurance measure to assess the functionality of laboratory critical equipment and instruments
examples of personal protective equipment (PPE)
lab coat, mask, gloves, etc.
what are quality assurance standards (QAS)
standards set by the FBI that are specific to DNA testing laboratories
what does SWGDAM stand for and what does it do
- the acronym for the Scientific Working Group on DNA Analysis Methods
- SWGDAM provides recommendations to the FBI and the United States forensic DNA community on quality assurance standards, research, protocols, and methodologies
what is the abacard hematrace test
- presumptive test for blood
- indicates human/non-human source for blood
what is acid phosphatase and what is it used for
- presumptive test for seminal fluid
- AP is an enzyme secreted in higher amounts by the prostate gland than anywhere else
what does azoospermic mean
- absence of sperm in ejaculate
- result of vasectomy
what is bulk evidence
any physical items collected at the crime scene
what are consumed items
when the entirety of the original evidence is used for testing; there is no excess to retain or re-test
what is contamination
the unintentional introduction of exogenous DNA into a sample or control during DNA testing
what are cuttings
- taken when the evidence examined is porous and there is an expectation that the biological material intended for analysis can penetrate past the surface
- for evidence, 1cm^2 - 1.5cm^2 is removed
- for references, 0.5cm ^2 - 1cm^2 is removed
- prepped for extraction in flip-cap 1.5mL conical tubes
what is documentation
- notes of the examination contemporaneous
- includes submission numbers, exhibit numbers, item descriptions, observations, photographs, SP#s, reagent lot numbers, individuals involved, and chain of custody
what is evidence
- anything that is collected from the crime scene
- swabs, bulk (weapons, clothing, tools, consumables), sexual assault kits (clothing, bedding, towels, condoms, devices), miscellaneous (vehicles, bones, hairs)
what are extraction sample types
- sexual assault kit samples: intimate and trace samples are processed differently
- blood: lots of DNA
- trace/contact: skin cells
- hair: root only
* hair shaft required for mitochondrial DNA testing
