19.07.14 Internal QC validating new methods Flashcards
Internal quality control
- Activities undertaken to detect, reduce and correct deficiencies in a labs internal analytical process
- Ensures procedures are fit for purpose
What steps are an essential part of IQC
- Validation
- Verification
What is verification
- Confirmation, through provision of objective evidence, that specified requirements have been fulfilled (doing a test correctly)
- Assessing kits/reagents/ software is fit for use
What is validation
Confirmation, through the provision of objective evidence, that the requirements for a specific intended use or application have been fulfilled (doing correct test)
-Includes clinical utility
Steps involved in a validation
- Description of process/equipment being evaluated
- Intended use
- Aims/ objectives
- Defined acceptance criteria
- Evaluation process (sample type etc)
- assessment of uncertainty of measurement
- Record and review outcomes (reproducibility, limits, sensitivity, specificity)
What is ACCE
- Analytical validity
- Clinical validity
- Clinical utility
- Ethical, legal and social implications of genetic testing
What is the purpose of ACCE framework?
Key components of genetic test validation
How many steps is analytical validity
3 steps
1) Pre-analytical (sampling, transportation, labelling)
2) Analytical (preparation of sample and carrying out analysis)
3) Post-analytical (result interpretation and reporting)
Main difference between validation and verification
- Validation is carried out when there is no suitable performance specification available, i.e. a novel test. It defines performance characteristics of a test.
- Verification compares performance characteristics of test with specifications.
What parameters are evaluated during validation/ verification
- Sensitivity
- Specificity
- Accuracy
- Trueness
- Precision
- Repeatability
- Reproducibility
- Robustness
- Limit of detection
- Limit of quantification
What is sensitivity
The proportion of positive results correctly identified by a test
What is specificity
The proportion of negative results correctly identified by a test
What is accuracy
How often a test gives the correct result (positive or negative)
What is trueness
- For quantitative tests, where results can have any value between two limits, this is a measurement of how close the test result is to the reference value.
- Deviation from reference value indicates a systematic error or bias.
What is precision
- Degree to which separate measurements differ
- Can be expressed as the standard deviation of a set of replicate results or the confidence interval around the mean.
