Optimising QC Lab Testing
QC test methods and the overall testing approach employed in laboratories can themselves be inherently wasteful. What steps should be taken to identify and eliminate such waste?
Short term volatility in overall workload or in the mix of samples (Mura) is by far the biggest lean opportunity in most labs and this should always be tackled first when leaning a lab. This usually means introducing leveling, flow, defined repeating test sequences and standard work. After this the Muda (waste) needs to be tackled and labs typically have significant amounts of waste.
In lean terms waste (muda) is defined as any activity which consumes resources but creates no value. Specifically in laboratories a number of wasteful practices are commonly encountered, which include: excessive planning and scheduling, excessive documentation and poor documentation Right First Time (RFT), inefficient investigation processes, and various kinds of Non-Value Add (NVA) activity in the testing process itself. This opinion focuses on waste elimination in the testing process, and addresses:
- Streamlining the Overall Test Process
- Combining Similar Tests into Single Runs
- Eliminating Unnecessary Testing
1. Streamlining the Overall Test Process
The principle means of achieving this is to design standard work, by documenting the individual steps in a particular test, identifying elements which don’t add direct value and disturb analyst flow, and establishing the most efficient method of completing the test. In designing standard work and corresponding roles some other factors should also be considered:
- Poor Test Methods. Tests that frequently fail and lead to wasteful rework should be the focus of project activity for improvement.
- Extending System Suitability’s. At the time of validation the main concern is to get test methods up and running in the lab and little consideration is given to lab operations. A longer suitability, when possible, will allow for greater batching of samples and will reduce the number of necessary set-ups.
- Extending Mobile Phase/Standard/Sample Expiry. For the same reasons as the previous example.
- Automation of Laboratory Equipment. Wastes associated with excessive analyst hands on time and waiting can be reduced through appropriate automation of laboratory equipment e.g. automatic sampling and injection for dissolution.
- Management of Consumables.
- Purchasing of pre-prepared solvents and reagents.
- Centralised preparation role(s), which will reduce the number of set-ups and increase consistency.
- Kanban for replenishment of consumables.
- Work Cells. Reduce the waste associated with analyst motion with a lab layout that corresponds to the standard work roles.
2. Combining Similar Tests into Single Runs
There is often scope to combine different tests into single runs reducing the number of necessary set-ups. For example, two products required HPLC analysis:
- The test methods required the same mobile phase, HPLC columns and system conditions.
- The test methods differed in sample and standard preparations and run time.
3. Eliminating Unnecessary Testing
The waste of over-processing appears quite often in labs in the form of unnecessary testing:
- Performing More Testing than is Registered. Information only testing is the main culprit here, particularly in the case of stability studies, and should be challenged when analysing the laboratory workload.
- Poor Communication. For example, problems with a batch may be detected by manufacturing after submission of samples to QC. After resolution of the issue samples are submitted again resulting in a doubling up of testing. A signal should be sent to the lab to halt testing on the first set of samples when the problem was detected.
- Overlapping Test methods. Observed when the use of a new test method has been initiated and the old method has not been removed by registration, e.g. HPLC degradation (new) and TLC degradation (old) run together.
- Unnecessary Stability Time-Points. Occurs when batches are not packaged within a short enough period of their initial assay.
- Reduced Testing. Particularly relevant for raw materials, it should be applied to materials that constitute a large portion of the workload, and which display satisfactory vendor compliant history.
This list is not exhaustive but serves to provide some points to consider. As always in choosing which projects to implement a weighting system should be used where factors such as cost saving, time saving and time to implement are used to rank improvement ideas in order of priority.
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