Autoanalysers/automation Flashcards
Why were autoanalysers built?
- Originally the Biochemistry laboratory used to perform tests manually
- The first automated analyser “AutoAnalyzer” was introduced in 1957 (20 samples at a time)
- Autoanalysers have been built in response to demand – ~2,000 samples daily and your average sample has 10 tests requested on it!
- Creatinine’s used to go from 30 a day to 3,000!
- Increase turnaround times (from 2 hours to 15 minutes!)
How do autoanalysers modernising pathology
- Standardise testing and improve resilience
- Improve quality and efficiency
- Manage demand and improve value for money
- Invest in the latest technologies
What are the benefits of autoanlysers to patients, staff and the NHS
Patients – Improved access to specialist tests, sharing results across sites
Staff- Training and development
NHS – Save and re-invest that money
Automation vs Mechanisation
Mechanisation:
• Using devices to replace, refine or extend human effort: e.g. capping/de-capping
Automation:
• Mechanisation with process control and use of computers helps with aspects of this: e.g. sample analysis
What happened before automation:
- All steps performed manually
- High chance of human error
- Time consuming
- Lost/Misplaced/wasted samples
What does automation allow?
- Electronic bar-coding for identification and test requests
- Tracking of sample throughout process
- Automatic aliquot for the sharing of samples
- Automated analysis on multi assay analysers on a single sample
- Electronic result collection and reporting
- Minimal variation and error
- Less sample and reagent
- Reflex testing
Types of analyser: Continuous flow
Tubing flow of reagents and patient samples, separated by air bubbles
Types of analyser: Centrifugal
Use of centrifugal force to mix a sample aliquot with a reagent and a spinning rotor and to pass the reaction mixture through a detector
Types of analyser: Discrete
• Robotic sampling arm and the use of single testing cuvettes for each reaction and only perform tests ordered on each sample
Explain how continuous flow analysers work
- Samples, reagents and diluents are introduced into a system of continuous tubing
- Spectrophotometric
- Sample probe placed in distilled water
- Does not allow test selection – all tests are performed even if they have not been requested
- Machine runs continuously and continually draws in reagents (costly and wasteful!)
- Monitor for bubble uniformity in the tubing
- Large machines
How do centrifugal analysers work?
What are the advantages and disadvantages?
Introduced in 1968
- Sample and reagent are pipetted into a cuvette
- Sample and reagent is mixed and the rotor containing the cuvette is spun and mixture flows over the walls into the reaction chamber – followed by a sudden stop
- Advantages include small sample and reagent volumes
- Disadvantages include that only one analyte can be measured each time (batch analyser)
How do discrete analysers work?
What are the advantages and disadvantages?
- Sample and reagent are added to an individual cuvette or reaction vessel
- Can run multiple tests on one sample (each sample is treated independently)
- Multiple samples one test at a time
- High throughput • Small sample volume
- Reaction chamber is temperature controlled
- Random access
- Almost completely replaced flow and centrifugal
- Costly
Workflow engineering:
Continuous flow
Sequential or Parallel
Workflow engineering:
Random acess
Random Access – STAT
Urgent Samples
• Can’t afford to waste time – front loading?
Re-runs
• LIMS error? Sample error? Bubble? Barcode error?
Add-ons
• If it’s urgent, do you have time to run it with routine samples?
What are the components of an analyser?
Total automation-Abbott
Instrument evaluation
- Run routine samples on the “old” analyser and run them on the new analyser for comparison
- Differences in methodology and results?
- Statistically analyse data to see variation
Levey-Jennings
- Monitor assay performance using a Levey-Jennings plot
- Mean is plotted and values within +/- 2SD are usually accepted
- Series of data points that allows you to monitor precision and accuracy
- Apply the Westgard rules – 6 rules to evaluate the assay performance - Random and Systematic errors
