PRINCIPLES OF CLINICAL CHEMISTRY AUTOMATION

AUTOMATION IN CLINICAL CHEMISTRYThe modern clinical chemistry laboratory uses a high degree of automation. Many steps in the analytic process that were previously performed manually can now be performed automatically.This Permits the operator to focus on tasks that cannot be readily automated and increasing both efficiency and capacity.

AUTOMATION IN CLINICAL CHEMISTRYThe analytic process can be divided into three major phases preanalytic, analytic, and postanalyticcorresponding to sample processing, chemical analysis, and data management, respectively.Substantial improvements have occurred in all three areas during the past decade. The analytic phase is the most automated, and more research and development efforts are focusing on increasing automation of the preanalytic and postanalytic processes.

WHY AUTOMATION?Increase the number of tests by one person in a given period of timeMinimize the variations in results from one person to anotherMinimize errors found in manual analyses equipment variations pipettesUse less sample and reagent for each test

TYPES OF ANALYZERSContinuous FlowTubing flow of reagents and patients samplesCentrifugal AnalyzersCentrifuge force to mix sample and reagentsDiscreteSeparate testing cuvets for each test and sampleRandom and/or irregular access

CONTINUOUS FLOWThis first AutoAnalyzer (AA) was a continuous-flow, single-channel, sequential batch analyzer capable of providing a single test result on approximately 40 samples per hour. Analyzers with multiple channels (for different tests), working synchronously to produce 6 or 12 test results simultaneously at the rate of 360 or 720 tests per hour.

In continuous flow analyzers, samples were aspirated into tubing to introduce samples into a sample holder,bring in reagent, create a chemical reaction, and then pump the chromagen solution into a flow-through cuvette for spectrophotometric analysis.CONTINUOUS FLOW

CONTINUOUS FLOWThe major drawbacks that contributed to the eventual demise of traditional continuous-flow analyzers in the marketplace were significant carry-over problems and wasteful use of continuously flowing reagents.

CONTINUOUS FLOWContinuous flow is also used in some spectrophotometric instruments in which the chemical reaction occurs in one reaction channel and then is rinsed out and reused for the next sample, which may be an entirely different chemical reaction.

CENTRIFUGAL ANALYZERSDiscrete aliquots of specimens and reagents are piptted into discrete chambers in a rotorThe specimens are subsequently analyzed in parallel by spinning the rotor and using the resultant centrifugal force to simultaneously transfer and mix aliquots of specimens and reagents into radially located cuvets.The rotary motion is then used to move the cuvets through the optical path of an optical system

DISCRETE ANALYZERSDiscrete analysis is the separation of each sample and accompanying reagents in a separate container. Discrete analyzers have the capability of running multiple tests on one sample at a time or multiple samples one test at a time. They are the most popular and versatile analyzers and have almost completely replaced continuous-flow and centrifugal analyzers.

DISCRETE ANALYZERSSample reactions are kept discrete through the use of separate reaction cuvettes, cells, slides, or wells that are disposed of following chemical analysis.This keeps sample and reaction carryover to a minimum but increases the cost per test due to disposable products.

HITACHI 902 ANALYZER

WITH AUTOMATION THERE IS STILL SOME VERY BASIC STEPSSpecimen preparation and IdentificationLabeling still critical Programming of instrument

Laboratory personnel must perform and observe:Quality AssuranceQuality Control

TOTAL LABORATORY AUTOMATION

SELECTION PROCESSWhat is your labs workload like?Discrete or large batch testing?Single instrument or multiples?Storage of reagentsNeed refrigeration or freezing? expenseKept at room temperature until reconstituted

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POINT OF CARE TESTING

DEFINITIONPoint-of-care testing (POCT) has been defined by the College of American Pathologists (CAP) as those analytical patient-testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories.

PLACE OF ANALYSISPhysicians officesOperating roomsEmergency roomsIntensive Care UnitsHome health carePatient performed

PERSONNEL ISSUESMost often performed by non-laboratoriansPhysiciansNurses or nurses aidesRespiratory techniciansNot specifically trained in the requirements for accurate testing and interpretation

LABORATORY SUPPORTLaboratory still responsible for resultsTherefore responsible for training and management of POCT programsLaboratory must build a structure to support and facilitate POCT

SUPPORT STAFFDirector - PhD, MD or laboratory scientist or pathologistPOC Coordinator laboratory scientist with high level technical & interpersonal skillsPOC Trainers designated person(s) for problem solving etc.

COMMON APPLICATIONSGlucose TestingChemistriesElectrolytesBlood gasesHematologyCoagulation ACTHematocrit