Presentation on theme: "Stacey Sandell 22 nd October 2009 – Laboratory Management."— Presentation transcript:
Stacey Sandell 22 nd October 2009 – Laboratory Management
◦ Quality – Reliably and repeatedly attaining a standard of excellence. ◦ Quality Control – Use of scientific methods to maintain the most accurate data possible. ◦ Quality Assurance – A program monitoring and controlling laboratory procedures and results, to insure the reliability of results.
The World Health Organisation (WHO) External Assessment of Health Laboratories (1981) usefully describes Internal Quality Control (IQC) as “the set of procedures undertaken by the staff of a laboratory for continuously assessing laboratory work and the emergent results, in order to decide if they are reliable enough to be released”. IQC applies to all staff all of the time. Staff training is crucial.
Examples: ◦ Acceptance of suitably labelled samples which match the referral form. ◦ Checking tube transfers. ◦ Visual inspection and quantification of extracted DNAs. Allows a rapid response to failure. ◦ Storage of DNA. ◦ Recording current batch and lot numbers. ◦ If using kits use exactly as specified by the manufacturer (storage conditions, expiry dates and protocol).
Examples: ◦ Routine maintenance of machines and calibration of laboratory equipment. e.g. PCR machines and pipettes. ◦ Using suitable controls for each test. If appropriate using controls which are at the limit of the test. ◦ SNP checking primers. ◦ Staff training. ◦ Results checking and confirming certain positive results. ◦ Checking demographic information before report is released. ◦ Follow SOPs and best practice guidelines. ◦ Accurate filing. ◦ Audit can help to assess quality control.
Internal validation is performed on newly designed techniques/diseases before they enter diagnostic service to establish if they are fit for purpose. Validation is the process by which we acquire the necessary information to: ◦ Assess the ability of the procedure to obtain reliable results. ◦ Determine the conditions under which such results can be obtained. ◦ Define the limitations of the procedure. Commercial kits have already been extensively validated by their manufacturers, but they should always undergo internal verification to insure that the product works as it is intended.
JAK2 – detection of the acquired point mutation V617F using a combination of ARMS PCR and pyrosequencing. Validation ◦ Changes were made to the published ARMS method because the specificity was too low. ◦ Control band added to ARMS method. ◦ 100% plasmid control mixed with normal to establish limits of both tests. ◦ Optimum conditions established. ◦ SOP written. Quality control ◦ 2%, 12% and 100% mutant controls on every run. ◦ Multiple water controls for pyrosequencing. ◦ Repeat discrepant results.
CSCE – technique used as the primary screen in the high throughput laboratory. Extensive validation by NGRL: ◦ Mutation position and GC content validated. ◦ Each fragment optimised to give optimum peak height. ◦ Over 300 known mutations tested (blind). Quality control ◦ Positive control, polymorphism control and water control for each fragment. ◦ Resequence normals if shift detected on CSCE. ◦ Peaks need to reach a minimum height.
Benefits of moving to automation: ◦ Fully automated systems have complete sample tracking. ◦ Standardised conditions. ◦ Larger capacity and faster throughput of samples. ◦ Less hands-on time. ◦ Reduced handling of reagents and samples. ◦ Batch information automatically electronically stored.
Drawbacks of moving to automation: ◦ Increased risk of product carry over. ◦ Often associated with a change in method (primer redesign and optimisation of new technique). ◦ Difficult to get all fragments to work under standard conditions. ◦ Machine breakdown (difficult to convert from automated to manual). ◦ Some step cannot be performed by the robot (check gels). ◦ More random failures.
Maintenance of quality. ◦ Concurrent/parallel runs. ◦ Blind testing. ◦ Lots of controls Lots of water controls. ◦ Optimisation to get standardisation. Peak height is important. ◦ Extra checks for sample tracking. Scan tubes and batch plates. ◦ Pipetting accuracy. Verification as already validated by manufacturer.
Maintenance of quality. ◦ Check for carry over. Wax. PCRs. ◦ Check files generated by automated systems. Check all scenarios (1-92 samples). Comparison program. ◦ Intensive training. ◦ Regular maintenance and calibration of robots.
EMQN draft best practice guidelines for laboratory quality control (2002) CMGS draft guidelines for internal quality control of sample reception and DNA extraction (2004). NGRL website (Wessex) – for examples of validation