FRSC 3020 Flashcards
Quality Control
Most basic level of quality– making sure product or service is OK. Doesn’t ensure quality, only points out lack of quality.
Quality Assurance
Aims to prevent non-conformities. Considers related activities like training, document control and audits. (Safety)
Horse in the Stall Example
QC is periodically checked to make sure the horse is in its stall.
QA is: making sure that there is a functional lock on the stall door that all stable hands are trained to use.
Making sure that all staff understand the importance of locking the door when the horse is in the stall.
Quality Management
Also includes quality improvements and aims to look at the quality management system as a whole.
Quality International Organization for Standardization (2)
- Has a standard for quality management systems.
- Published over 22,000 international standards covering almost every industry in existence inlduing forensics.
Management System Must contain: (4)
- Management (planning, goals, objectives).
- Resources (people, tools, equipment).
- Service/product realization (whatever is involved in creating the product).
- Monitoring (feedback loop).
MRS&M
Mister and Misses
Types of Errors in QC/QA in Forensics
Type 1: false positive.
Type 2: false negative
Which error type would they prefer in Court
Court system would prefer false negative(Type 2)
Which labs are captured in the QA
- CODIS
- FBI
- CFS
What is method validation?
The process of establishing performance characteristics and the limitations and influencing factors on a method
When is validation needed?(3)
- Whenever the method is changed and the change is outside the original scope of the method.
- Before introduction of a new method into routine use.
- Whenever conditions change for which a method has been validated– eg. anew instrument with different characteristics is bought.
WBW
Women Bitch Wednesday
The 3 R’s
Robust method:
- successful results are obtained a high percentage of the time
- The robustness of an analytical procedure is a measure of its capacity to remain unaffected by small variations
- Provides an indication of a method’s reliability during normal usage.
Reliable method:
-the obtained results are accurate and correctly reflect the sample being tested.
Reproducible method:
- the same or very similar results are obtained each time a sample is test.
Examples of Evidence Control(4)
- Unique identifier
- chain of custody (people, date, time)
- procedures to prevent contaminiation
- controlled access areas.
CUPP
3 things personnel must complete or have to work in a forensic lab
- have education, training and experience
- Documented training program: including a manual, practical exercises, participation in continuing education.
- Probation period and competency testing before completing independent casework
acronym: PhD
3 Levels of validation
Developmental validation:
- commonly performed by commercial manufacturers of novel methods or technologies (more extensive than internal validation)
Internal validation:
- performed by individual labs with new methods are introduced.
Performance checks:
- can be performed with every run (set of samples).
DIP
dipsy doo da
Developmental Validation(3)
- Demonstration of the accuracy, precision and reproducuibilty of a procedure.
- Completed by the manufacturer, technical organization, academic institution, government laboratory, or other party creating something new.
- Must precede the use of a novel methodology for forensic analysis.
Internal Validation
- The internal validation process should include the studies detailed below encompassing a total of at least 50 samples:
- Known and nonprobative samples, reproducibility and precision, match criteria, mixture studies
- Sensitivity and stochastic studies, contamination, qualifying test
Define Precision
How closely grouped your data is
Define Accuracy
How close your data is to the actual answer.
Limit of Detection (LOD)
The lowest content that can be measured with reasonable statistical certainty.
Limit of Quantitative Measurement (LOQ)
The lowest concentration of an analyte that can be determined with acceptable precision (repeatability) and accuracy under the stated conditions of the test.
System Stability
Fitness of the sample or test to produce reliable and accurate results over time.
Steps to validating a method(5)
- Decide on analytical requirements: sensitivity, resolution, precsions, etc.
- Plan a suite of experiments.
- Carry out ht experiments.
- Use data to assess fitness for purpose.
- Produce a statement of validation: scope method.
DCUPP
validate big boobs
Assumptions when performing validation(4)
- The equipment on which the work is being done is broadly suited to the application; it is clean, well maintained and calibrated.
- The staff carrying out the validation are competent in the type of work involved.
- There are no unusual fluctuations in laboratory conditions and there is no work being carried out in the immediate vicinity likely to cause interferences.
- The samples being used in the validation study are known to be sufficiently stable.
