CC LAB: AUTOMATION

• Definition of Terms:

  • Automation: The process where an analytical instrument performs many tests with minimal involvement of an analyst
  • Batch analysis: Type of analysis where many specimens are grouped in the same analytical session
  • Carry-over: The transport of analyte or reagent from one specimen reaction into and contaminating a subsequent one
  • Continuous-flow analysis: Type of analysis where each specimen in a batch passes through the same continuous stream at the same rate
• • Discrete analysis: Type of analysis where the sample is aspirated into the sample probe and then delivered into a reaction cup
  • Dwell time: Minimum time from initial sampling to the production of a result
  • Multiple-channel analysis: Type of analysis where each specimen is subjected to multiple analytical processes
  • Parallel analysis: Type of analysis where all specimens are subjected to a series of analytical processes at the same time
  • Random-access analysis: Configuration of an automated analyzer where analyses are performed on a collection of specimens sequentially
• • Sequential analysis: Type of analysis where each specimen in a batch enters the analytical process one after another
  • Single-channel analysis: Type of analysis where each specimen is subjected to a single process
  • Throughput: The number of specimens processed by an analyzer during a given period of time
  • Workstation: A clinical laboratory workstation dedicated to a defined task
• Automation:

  • Enables laboratories to process larger workloads without comparable increases in staff
  • Used for test performance, processing and transport of specimens, loading of specimens into automated analyzers, and assessing test results
• History of Automation:

  • First automated analyzer was the "Autoanalyzer" by Technicon in 1957
  • First commercial centrifugal analyzer was a spin-off technology from NASA outer space research in 1970
  • Automatic Clinical Analyzer (ACA) by DuPont (now Siemens) in 1970 was the first non-continuous flow, discrete analyzer with random-access capabilities
  • Kodak Ektachem (now Vitros) Analyzer in 1978 was the first to use microsample volumes and reagents on slides for dry chemistry analysis
• Basic Concepts and Approaches to Automation:

  • Advantages of automation include decreased human factor, increased test performance, minimized variation in results, and accuracy not dependent on operator skill
  • Eliminates potential errors of manual analyses and uses small amounts of reagents and samples
• Automated System Designs:

  • Total Laboratory Automation employs an integrated track system linking all workstations together
  • Modular Integrated Systems link multiple laboratory disciplines into a single testing platform
  • Stand-alone systems automate specific sections of the process that are still manual operations
• Classification of Automated Analyzers:

  • Continuous Flow Analyzer: Samples flow through a common reaction vessel, significant carryover problems
  • Discrete Analyzer: Samples travel through the instrument in its own reaction vessel, each test reaction takes place in a separate compartment
  • Centrifugal Analyzer: Developed from space-aged technology, samples and reagents mixed together and flowed by centrifugal force into separate cuvettes
• Centrifugal analyzers:

  • Samples and reagents mixed together, reacted, and flowed by centrifugal force into separate cuvettes for spectrophotometric analysis
  • Only one test type can be performed each time
• Sequential:

  • Performing a set of test reactions in a particular order on each sample in the order received
• Batch:

  • All samples loaded at the same time, and a single test conducted on each sample
• Parallel:

  • More than one test analyzed concurrently on a given clinical system
• Random access:

  • Any test can be performed on any sample in any sequence
• Automated analysis technologies:

  • Bar coding
  • Optical character recognition
  • Voice identification
  • Radio frequency identification
  • Touch screens
  • Light pens
  • Hand print tablets
  • Optical mark readers
  • Smart cards
  • Automated specimen inspection to identify sample identification errors and sample integrity issues
• Specimen preparation and identification:

  • Preparation of the sample for analysis is a manual process in most laboratories
  • Alternatives include the use of robotics or front-end automation, bypassing specimen preparation by using whole blood for analysis, and using barcode-labeled tubes
• Specimen loading and aspiration:

  • Circular carousels or rectangular racks as specimen containers
  • Instrument determines the slot number containing the last sample and terminates the analysis after that sample
  • Tubes are typically decapped before sampling
  • Common problem: Carryover
  • Loading zone: area where specimens are held inside the instrument before analysis
• Reagent systems and delivery:

  • Open-system analyzer allows operator to change analysis parameters and use reagents from various suppliers
  • Liquid reagents for open systems are less expensive than closed analyzers
  • Techniques of preservation include refrigeration, dried tablet form, or combining stable components at the moment of reaction
  • Reagent delivery techniques include syringes, piston-driven pumps, and pressurized reagent bottles connected to dispensing valves
• Chemical reaction phase:

  • Mixing methods include forceful dispensing, magnetic stirring, vigorous lateral displacement, rotating paddle, and ultrasonic energy
  • Separation involves a high reagent-to-sample ratio and short reaction time
  • Incubation maintains required temperature and provides delay for color development
  • Measurement phase methods include UV light, fluorescent, flame photometry, ion-selective electrodes, gamma counters, and luminometers
• Signal processing and data handling:

  • Accurate calibration is essential for reliable results
  • Proper use of standards reflects data on a standard curve for interpreting sample results
  • Instruments' computer goes into data acquisition and calculation mode after calibration
  • Signal processing may involve signal averaging with hundreds of data pulses per second
• Future trends in automation:

  • Automation will continue to evolve with system integration and miniaturization
  • Automated analyzers may have artificial intelligence for decision-making
  • Spectral mapping and multiple wavelength monitoring will become standard with high-resolution photometers and polychromators