Automation in Clinical Laboratory PDF

W4: AUTOMATION IN THE CLINICAL LABORATORY Clinical Chemistry (LECTURE) BS Medical Laboratory Science │PROF. Jolo Dadios│ 3rd year, 1st Sem: Prelim AUTOMATION IN THE CLINICAL LABORATORY Parallel testing – more than one tes...

W4: AUTOMATION IN THE CLINICAL LABORATORY Clinical Chemistry (LECTURE) BS Medical Laboratory Science │PROF. Jolo Dadios│ 3rd year, 1st Sem: Prelim AUTOMATION IN THE CLINICAL LABORATORY Parallel testing – more than one test is analyzed Goals of Laboratory Automation concurrently on a given specimen Rapid results Random access testing – any test can be performed Increase in the number of tests performed on any sample in any sequence Reduction in turnaround time Sequential testing – multiple test analyzed one after Eliminates the needs for staff (personnel) increase another on a given specimen Improvement in laboratory safety Open reagent system – a system other than Errors in calculations and transcription are reduced manufacturer’s reagent can be used Better precision and accuracy Closed reagent system – operator can only use Reduction of costs manufacturer’s reagent Expansion of laboratory testing to generate more Stand-alone – instrument from a single discipline with revenue automated capability Reduction in laboratory errors Automated stand alone – instrument from a single discipline with additional internal automated capability (ex. Auto-repeat and auto-dilute) General Considerations for Laboratory Autonomation Modular workcell – at least two instrument from a Union issues single discipline with one controller Power and cooling requirements Multiple platform – instrument able to perform test Inventory management from at least two disciplines Cross-training of staff Integrated modular system – at least two analytical LIS interface needs modules supported by one sample and reagent Auto verification- “double-checking of the results” processing and delivery system Peak volume testing Pneumatic tube system – transports specimens Staff involvement quickly from one location to another. STAT testing Centralized customer service area Site visit Disadvantages: There maybe limitations in the methodology that can be used MT is often discouraged from making observations and using their own judgment about potential problems. Many systems are impractical for small number of General Terms samples Expensive to purchase and maintain Throughput: Maximum number of tests generated per hour Turnaround: Amount of time to generate one result Steps in Automated Analysis Bar coding: Mechanism for patient/sample 1. SAMPLE ID - usually by barcode reader identification; used for reagent identification by an 2. TEST SELECTION - usually communicated by LIS instrument. 3. SAMPLING - usually closed-tube sampling from Dead volume: Amount of serum that cannot be primarily collection tubes. Some analyzers have short aspirated sample and clot detection. Carry-over: contamination of a sample by a previously 4. REAGENT DELIVERY - usually by syringes, pumps or aspirated sample pressurized reagent bottles. Vitros uses dry slides, Reflex Testing: Use of preliminary test results to Some offer reagent inventory. determine if additional tests should be ordered or 5. CHEMICAL REACTION - mixing and incubation canceled on a particular specimen, performed manually 6. MEASUREMENTS - visible and UV spectrophotometry, or automated ion-selective electrodes, fluorescence polarization Total laboratory automation - automated systems immunoassay, chemiluminescence, bioluminescence. exist for laboratories where samples are received, Most offer automatic dilution and retesting when centrifuged, distributed to particular instruments using a linearity is exceeded. conveyor system and loaded into the analyzer without 7. DATA HANDLING - concentration derived from operator assistance. This kind of automation is seen in calibration curve stored in analyzer large medical central laboratories and commercial 8. REPORTING - usually reported to LIS through interface laboratories where the volume of testing is high. 9. TROUBLESHOOTING - can be done by modem on many analyzer Designs: Sequential analyzer – performs only one test at a time Batch analyzer – performs only one kind of test but multiple specimen Parallel analyzer – performs numerous test but only for a single specimen Random access analyzer – performs test in any order Terminologies Batch analysis – all samples are loaded at the same time and a single test is conducted on each sample TECHNICON, 1957 Parts: ➔ introduction of the first automated analyzer. Sampler – holds the cups containing the standards and “AutoAnalyzer” (AA) specimens for analysis, which are introduced into the ➔ a continuous flow, single-channel, sequential batch analytical system by means of aspiration, in a preset ➔ analyzer capable of providing a single test result on sequence and a pre-selected rate. approximately 40 samples per hour. Pumps and Manifolds – for continuous and proportional delivery of samples, reagents or gasses. Simultaneous Multiple Analyzer (SMA) series This is analogous to pipetting in manual techniques ➔ next generation of Technicon instruments to be Dialyzer – employs dialysis through a semipermeable developed. membrane to separate proteins from the analytes, thus ➔ SMA-6 and SMA-12 eliminating the need for manual deproteinization ➔ analyzers with multiple channels (for different tests), techniques. working synchronously to produce 6 or 12 test results Heating Bath – for heating and incubating the reaction simultaneously at the rate of 360 or 720 tests per hour mixture and fixed temperature 1970 Examples: ➔ the first commercial centrifugal analyzer was introduced Technicon Autoanalyzer II – capable of running three as a spinoff technology from NASA outer space different tests at 60- 80 samples per hour. research The Technicon Autoanalyzer II (AAII) is the instrument that most EPA methods for automated colorimetric Dr. Norman Anderson analysis. ➔ developed a prototype in 1967 at the Oak Ridge National Laboratory as an alternative to continuous flow technology, which had significant carryover problems and costly reagent waste. ➔ He wanted to perform analyses in parallel and also take advantage of advances in computer technology The AutoAnalyzer II is a second generation segmented Automatic Clinical Analyzer (ACA) flow analyzer that uses 2 millimeter ID glass tubing and ➔ the first non continuous flow, discrete analyzer as well pumps reagent at flow rates of 2-3 milliliters per minute. as the first instrument to have random access SMA 6/60 – capable of running 6 tests at 60 samples capabilities, whereby stat specimens could be analyzed per hour out of sequence on an as needed basis. SMA 12/60 – capable of running 12 tests at 60 samples ➔ Plastic test packs, positive patient identification, and per hour infrequent calibration were among the unique features SMAC – capable of running 40 tests at 120 samples per of the ACA. hour Kodak Ektachem (now VITROS) Analyzer (now OrthoClinical Diagnostics) in 1978 ➔ This instrument was the first to use microsample volumes and reagents on slides for dry chemistry analysis and to incorporate computer technology extensively into its design and use. FOUR MAIN TYPES OF AUTOMATIC ANALYZER DISCRETE SAMPLING ANALYZER Continuous Flow System Principle Principle: Each sample reaction is handled in a separate All samples are carried through the same analysis compartment and does not come into contact with pathway. another sample. The samples and standards are All samples automatically pass from one step to another handled on a batch basis and must be brought before without waiting to bring the samples to the same stage proceeding to the next procedure. All reactions must be of completion. carried out until equilibrium is reached. The reactions are not necessarily carried to equilibrium since samples and standards are treated exactly alike. Examples: One sample, one test (analyte) DUPONT ACA (Automatic Clinical Analyzer) – reagents of each test are packaged in a special plastic Features: pack with a rigid header. This pack serves as the Use of plastic tubes of different diameters and a reaction chamber and test cuvette for photometric peristaltic pump for continuous pumping of samples and analysis. reagents. This maneuver replaces the pipetting steps in Each test pack contains: the manual procedures. ○ Chromatographic column that removes Introduction of air bubbles interfering substances ○ To separate the sample and reagent streams ○ A gel filtration matrix to retard small molecules. into segments. ○ A protein precipitant column. ○ To separate one sample from the next ○ For continuous scrubbing of tubing ABBOTT ABA-100 BIOCHROMATIC ANALYZER, ○ Prevents cross contamination or carry over by ABA-200 and VP ANALYZER the previous specimen ○ Equipped with a single disposable plastic Removal of proteins by dialysis. 32-compartment molding, so that transfer of Flow-through cuvettes in interference filter photometers, final solutions for photometry is avoided using a fixed reference light path. ○ With complete immersion of the reaction Recorded read-out vessel in a water bath to achieve rapid rise to Modular design permitting interchanging of major parts. stable environment ○ Use of ultramicro samples (e.g. 5ul) ○ Problem of interference from serum and reagent color is overcome by taking  absorbance readings at two wavelengths, the GENERAL FUNCTIONS PROVIDED BY AUTOMATED so-called “bichromatic system.” ANALYZERS Collection and preparation of the Sample ○ Use of bar-coded labels on the samples which allow electronic identification of the sample and the tests requested Sample and reagent Measurements and Mixing ○ Automated measurements measure, aspirate and introduce samples into the analyzer reagents ○ Reagents and sample are combined in a BECKMAN ASTRA 8 and ASTRA 4 prescribed manner to yield a specific final ○ Microprocessor-controlled instruments concentration ○ Use of ultramicro samples ○ Mixing of reagents and samples can be done ○ Results are displayed on a screen and by by stirring, agitation or by some other device. printer Incubation ○ Multichannel analyzer in effect ○ This is simply a waiting period in which the text mixture is allowed time to react ○ Done at a specified, constant temperature controlled by the analyzer. Monitoring or Sensing the Reaction Result ○ Done by optical, thermal or electrical means ○ Some measurement can be done in the vessel, cell or cuvette where the reaction has taken place – this is known as situ-monitoring. CENTRIFUGAL FAST ANALYZERS As the rotor is accelerated, centrifugal force moves the Important Terminologies in Automation reagents and sample to a mixing chamber and then Test repertoire – number of tests that can be performed through a small channel into the cuvette. As the filled on instruments. cuvette rotates past a fixed light beam, the absorbance Selective – only performs requested tests. of the reaction is measured spectrophotometrically. Dwell time – minimum time required to obtain result EXAMPLES: after the initial sampling of the specimen. ○ CentrifiChem Cost – labor maintenance, reagents, calibration, quality ○ RotoChem control, consumables and capital. Test menu – a list of the analytes or tests that a laboratory would be able to provide for patient testing. Workload – the number of test results that are generated by a laboratory during a given time period. Walk-away capability – the ability of the operator to program the instrument to perform other tasks while the instrument processes the tests. Linearity – the range over which patient results can be reported without manipulating the sample (i.e. using a dilution). The linear range is generally defined by the values of the highest and lowest calibrations available AMERICAN MONITOR KDA for a particular instrument. ○ A computer controlled, single channel analyzer Sensitivity – the lowest value that can be reliably ○ Results are stored with subsequent print-out of detected by a method without providing a false positive collated patient results result. Specificity – the ability to measure only the analyte requested. Quantitating the Reaction Result Digital Computation ○ Usually restricted to certain mathematical functions (such as addition or subtraction) ○ A digital computer needs an analog-to-digital DRY SLIDE/THIN-FILM ANALYZERS converter to process the signals received from Principle the many types of sensing or monitoring A 16 mm square chip which contains several very thin devices. layers, accepts a metered drop of serum, spreads it ○ The converter changes the voltage or current evenly into a reagent layer, then confines the colored signal into a digital form which can then be product to the fixed area for reflectance processed by the computer. spectrophotometry. Analog Computation EXAMPLE: ○ Uses an electrical signal from the sensor, as ○ Kodak “EktaChem” from the photoelectric cell and compares it with uses reflectance measurement a reference signal as for the blank solution not used in drug test and alcohol test ○ It compares the two signals and takes the logarithm of the result as the final result for the unknown sample. Visualizing the Result ○ Visualizing the instrument readout is with the use of a television monitor (cathode- ray tube) or light emitting diodes. ○ The visualized readout can be converted to a hard copy by means of a paper or tape printout.  ○ Data printout information is transferred or transcribed to lab result slips or other permanent records. ○ If results are interfaced with a lab computer, this transcription process is done quickly and without errors, which may occur when transcription is done manually. Standardization ○ There is frequent standardization of methods ○ Once the standardization has been done, a well-designed automated system maintains or reproduces the prescribed conditions with great precision Transes by: A. S. Loyola