1. Automated Clinical Biochemistry Flashcards
What is an automated analyser?
- Medical lab instrument
- Designed to measure different chemicals + other characteristics in a number of biological samples
- Quickly + with minimal assistance
List the advantages of automation
Increased activity/productivity;
- high throughput: >120 tests available, >5000 samples/day, >250,000 results/day
- improved lab workflow
- management reports
- cost savings (less staff for menial/simple tasks)
- smaller sample volumes
Quality + reproducibility:
- reduction of human error
Faster turn-around-time;
- decreased hospitalisation time
- treatment improvements
- cost savings
Safer;
- less exposure of staff to hazardous materials
List the disadvantages of automation
If the lab doesn’t adapt well to automation, e.g. changes shift patterns, includes training, keeps the machines running 24/7
- misuse of tools
- expectations of increased productivity not achieved
Crash of automat (need backup);
- good support and maintenance essential
- expensive maintenance budget
Unhappiness of staff;
- boring/lonely work?
- must be lab wide project that includes all staff
List the processes required to produce lab result from automated equipment?
- sample reception: data entry + sample receipt
- labelling
- storage
- pre-analytics
- reagent supply + loading
- room for efficient set up of machinery
- specific analytical modules/chemistry analysis
- controls
- calibrations for specific assays
- quality control
- maintenance
- technical/clinical validation
- reporting
Describe the preanalytical steps from venepuncture to sample receipt in the lab
Test ordered by clinician
Phlebotomist IDs patient + collects sample in appropriate tube e.g.red tube with EDTA for all routine haematology.
Patient sample form correctly filled out and collection tubes labelled.
Samples immediately sent to lab or appropriately stored until transport alongside request form.
Samples arrive at sample reception in specimen bags (and disposed of in bag after analysis).
Written + printed forms must be completed or are rejected;
- requires patient identifiers on form AND tube.
- e.g. name, surname, hosp. no., NHS number, etc.
- check sample is correct type for test(s) required
Cards scanned after sample booked + logged in on ICE and Winpath;
- allows digital access via autocard viewer software
- whole process partly automated: OCR/OMR of forms, barcode scanning of forms + tubes
Where do samples recieved at the lab arrive from and how do they arrive?
Arrive by;
- pneumatic system
- courier
- porter system
- pathology transport
- personal delivery
Multiple sources;
- in/outpatients
- GPs surgeries
- referring hospitals
- sometimes private companies
Describe how samples are labelled and stored after booking
Samples relabelled if required;
- visible patient details + lab number
- barcode vertical for analysers to read
Sample put in analysers for testing OR stored/preserved appropriately.
After analysis all samples (routine) kept in cold room ~5 days unless reason to keep longer - then discarded in clinical waste.
Describe the tasks performed by automated preanalytic systems
- input buffer
- centrifuge unit
- destopper
- aliquoter
- bar code labeller
- restopper
- archiver
- output buffer
Who are the main suppliers of the reagents, “wet chemistry, etc., in the lab?
- Abbot diagnostics
- Beckman/coulter
- Roche diagnostics
- Siemens
What automated analytical system does the hospital use for chemistry analyses and what does it do?
Hospital uses Cobas system;
- Cobas 8000 data manager: single screen for instrument monitoring
- Core unit: loading capacity of 300 samples, 1000samples/hour
- ISE module: sodium/potassium/chloride, 900-1800 tests/hour
- Clinical chemistry/immunoassay module (homogenous)
- Reagent manager module: loading cassettes, etc.
- Clinical chemistry/immunoassay (homo)/HbA1c (whole blood measurements) module
- Heterogenous immunoassay module
- Module sample buffer (MSB)
The Cobas system does everything needed and is very compact (saves space instead of a machine/bench needed for each test).
What controls and calibrations are needed in the automated lab and why?
Optical readings: automated cell blanking with DI;
- confirms optical integrity of cells
- baseline for reaction measurement
Test kits with known values + positive/negative control reagents;
- special specimens inserted + treated as pt samples (exposed to same operating conditions)
- evaluate reliability of a method using stable material
- measure precision + accuracy
Appreciate calibration + result interpretation v. important as determine if IQC values pass/fail internal rules set by lab
- standards used to calibrate in analytical chemistry: primary + secondary
- calibration schedule set by manufacturer
Describe the primary standard used to calibrate in analytical chemistry
Standard solution = a solution with accurately known concentration
Primary standard:
- from first principles
- substance so pure that the amount of substance in mole can be accurately calculated from its mass
- e.g. sodium + choride
- method: calculate, weigh out NaCl + make up std containing 100mmol/L Na + 100mmol/L Cl
Describe the secondary standard used to calibrate in analytical chemistry
Standard solution = a solution with accurately known concentration
Secondary standard:
- specific standard prepped in the lab for a specific analysis (usually standardised against primary standard)
- value assigned; using international reference method, e.g. cholesterol OR assigned against international reference standard, e.g. total protein
What 3 analytical modules are mainly used in the biochemistry lab?
- Ion selective electrodes (ISE)
- Photometric
- Immunoassay (homogenous/heterogenous)
What is an ISE and what is it used for in analytical chemistry?
ISE = a sensor/transducer converting activity of a specific ion dissolved in solution into an electrical potential
Used to determine ionic concentration of substances in aqueous solution
