如何进行医学实验室风险评估.pptx

How to Evaluate Risk in theMedical LaboratoryJames H.Nichols,PhD,DABCC,FACBProfessor of Pathology,Microbiology and ImmunologyMedical Director of Clinical Chemistry and Point-of-Care TestingVanderbilt University School of MedicineMedical Director,Clinical ChemistryNashville,Tennessee,USAjames.h.nicholsvanderbilt.edu 1Objectives1.Discuss the sources of error in the medical lab2.Review QC as a means of controlling analytical error3.Identify risk management as a total quality assurance of the testing process4.Describe regulatory changes adopting risk management in the laboratory 2Medical ErrorAn adverse event or near miss that is preventable with the current state of medical knowledge.(the Quality Interagency Coordination Task Force)Medical ErrorsInstitute of Medicine of the National Academies report 1999Medical errors kill 44,000-98,000 patients in US hospitals each year.“Number one problem facing health care”Lucien Leape,Harvard Professor of Public HealthMedical Errors2002 Commonwealth Fund report estimated that 22.8 million people have experienced a medical error,personally or through at least one family memberReinforces the 1999 IOM report,“To Err is Human”Annual costs estimated at$17 29 billionUS Agency for Healthcare Research and Quality(AHRQ)estimate medical errors are the 8th leading cause of death in the US higher than:Motor Vehicle Accidents(43,458)Cancer(42,297)AIDS(16,516)Laboratory ErrorsA review of the literature found the majority of errors occur in the pre and post analytical phases.Bonini P,Plebani M,Ceriotti F,Rubboli F.Clin Chem 2002;48:691-698.Many mistakes are called“lab error”,but actually due to poor communication,actions by others involved in the testing process,or poorly designed processes outside the labs control.Medical errors occur in prevention,diagnosis and drug treatment occur.Among errors in diagnosis;50%were failure to use indicated tests,32%were failure to act on results of tests,and 55%involved avoidable delay in diagnosis.Leape LL,Brennan TA,Laird N,et al.N Eng J Med 1991;324:377-84.7Historical Quality ControlQuality control historically used to reduce errors and prevent the release of incorrect results from the laboratory!Born from the 1950s industrial model of quality in analytical and factory processesQuality control is a stabilized surrogate sample analyzed like a patient sample containing known amount of measured analyte.If the analytical test system can achieve the desired result using a QC sample,then the system is stable and quality patient results are assumed to be produced.8Quality ControlAdvantagesQC has target values,if assay recovers target,then system is assumed to be stable(instrument,reagent,operator,sample)Shift in QC=Shift in quality patient results!Warns of test result problems before release to physicianQuality ControlDisadvantagesIf QC not analyzed frequently enough or lab fails to take action when QC fails,quality of patient results affected!With new autoverification or continuous release of results by chemistry and hematology analyzers-Possible to release patient results before a problem is detectedWhen a problem is detected,lab must go back and reanalyze patients since last“good”QC and possibly send out corrected results.Clinical action could be taken on erroneous results in the interim of correcting an unrecognized issue!Despite its limitations,QC remains an important means of detecting and preventing laboratory errors!1011Systematic ErrorsLiquid QC does a good job at detecting systematic errors,like:Reagent deterioration or preparationImproper storage or shipment conditionsIncorrect operator technique(dilution,pipette setting)Calibration errors wrong setpoint,factorsErrors which affect every test in a constant and predictable mannerErrors that occur from one point forward or for a limited period of time12Random ErrorsLiquid QC does a poor job at detecting random errors unless the error specifically occurs with the QC sample or increased result variability is noted.Errors which affect individual samples in a random and unpredictable fashion,like:ClotsBubblesInterfering substances13QC and Lab ErrorsQCQC09:0009:00Line Leak11:0001:15Hemolyzed sampleQC daily at 09:00,two levelsLine leak occurs at 11:00,dispenses partial reagent causing 25%decrease in values,not detected until next day QC at 09:00.(Systematic Error),must reanalyze all specimens since previous QC at 09:00,the previous day.Hemolyzed specimen(Random error)affects one sample14History of Quality ControlQuality control has been traditional means of managing error in the laboratory!CLIA 67 required daily QC as integral part of testing processCLIA 88 -reaffirmed“two levels of QC per test per day”(blood gases every 8 hours)CAP advocates daily QC through inspection and accreditationThe Joint Commission focuses on patient safety and preanalytic,analytic and postanalytic processesISO QC Recommendations15ISO 15189 5.6.1 The laboratory shall design internal control systems that verify the attainment of the intended quality of results.Special attention should be paid to elimination of mistakes in the process of handling samples,requests,examinations,reports,etc.Documentation should include quality control procedures based on manufacturer instructions for use.Internal Quality Control(internal to the laboratory)is defined as a set of procedures undertaken by laboratory staff for the continuous monitoring of operation and the results of measurements in order to decide whether results are reliable enough to be released.The regular analysis of QC materials can serve as an essential component of a laboratorys internal control system.16Quality in Laboratory TestingDespite analyzing the minimum required 2 levels QC/day,we have all experienced erroneous laboratory results!Quality is more than QC!Quality is:Testing that is safe and reliableAppropriate use of technology to meet medical needsTest results that can be trusted for medical managementA labs reputation depends on quality of its results!What should be the lab goals for errors?Unacceptable ErrorsDeaths/106 enplanements0.2 PPMDeaths/106 general anesthesia inductions2-5Viral transmissions/106 transfusions29Results 7 SD/106 automated chem tests100Lost bags/106 airplane passengers5000Failures/106 proficiency tests14,000Difference 5%/106 hematocrit testsup to 190,000Witte D&VanNess S.Frequency of Unacceptable Results in Point-of-Care Testing.Arch Pathol Lab Med 123:761,1999Sigma MetricsSigma metrics are an industrial measure of quality in a factory process -estimates rate of defects in productsGoal of sigma metrics:Improve customer satisfactionBalance number of rejected products with the increased cost required to improve processes(to lower defect rates)Six sigma consensus for balancing rejection against the increased costs of improving errors for industrial processes Six sigma was adopted and popularized into the clinical laboratories in 1990s18Sigma PerformanceNeed for Quality Laboratory TestingLaboratory testing influences 70%of all medical decisions.7 billion lab tests conducted in the U.S.annuallySilverstein MD.An approach to medical errors and patient safety in laboratory services.A white paper prepared for the Quality Institute Meeting,Making the Laboratory a Partner in Patient Safety.Division of Laboratory Systems,Centers for Disease Control and Prevention,April 2003.http:/www.phppo.cdc.gov/mlp/qiconference/Beyond Six SigmaWith 7 billion tests conducted in the US annually,six sigma(3.4 defects/million tests)means releasing 23,800 incorrect lab tests annually in the US!Any single result error could mean a misdiagnosis,failure to treat an illness or incorrect treatment selection!Virus contamination of blood product,Incorrect cancer diagnosisMissed heart attack!What if that wrong test result belonged to you or a family member?For a medical laboratory,six sigma is an unacceptable goal!We need to go“beyond six sigma”for laboratory performance,with a goal of ZERO errors that reach the patient!2122Risk DefinitionRisk the chance of suffering or encountering harm or loss(Websters Dictionary and Thesaurus,1993 Landoll,Ashland,Ohio)Risk is the potential for an error to occurRisk DefinitionISO/IEC Guide 51 Risk can be estimated through a combination of the probability of occurrence of harm and the severity of that harm RISK=(Frequency)x(Severity Harm)x(Detection)number of errors=greater risk harm=greater riskInability to detect an error=greater riskRisk is simply a rating scale to rank the order for addressing potential errors in lab(with limited available resources)23Medical ErrorsThe PersonEasier to blame a person than an institution for errors.In aviation,90%of quality lapses are judged to be blameless.The SystemActive failures due to personal interaction with systemLatent conditions,weaknesses in system due to design flaws or heirarchical decisionsNeed to engineer systems that prevent dangerous errors and are able to tolerate errors and contain their effects Reason J.BMJ 2000;320:768-770.Identifying Risk in the LaboratoryThere is no“perfect”device!Any device can and will fail under the right conditionsEvery device is different!(universal 2 levels QC/day doesnt fit every situation,may need more frequent QC especially if frequent staff turnover or unstable reagent)Any discussion of risk must start with what can go wrong with a test(errors)Lab tests are not fool-proof,for a sufficiently talented fool!26CLSI Project:EP23Laboratory Quality Control Based on Risk Management.James H.Nichols,Ph.D.,ChairholderEP23 describes good laboratory practice for developing a quality control plan based on manufacturers information,applicable regulatory and accreditation requirements,and the individual healthcare and laboratory setting 27EP23 Laboratory QC Based on Risk ManagementMedical Requirements for Test ResultsTest System Information:Provided by the manufacturer Obtained by the LaboratoryInformation about Health Care and Test-Site SettingInput InformationProcessRisk AssessmentOutputLaboratory Directors QC PlanPost Implementation MonitoringContinuous ImprovementRegulatory and Accreditation Requirements CLSI EP23 TableWhere is the Risk in the Process?28 What Could Possibly Go Wrong?Identifying Risk in the LaboratoryFollow the sample through the testing process!At each step,ask“What could possibly go wrong?”For each hazard identified,define a mitigation step,a way to minimize the risk of error occurring!Summarize the hazards and actions in a quality control plan!29Steps of the Testing ProcessPatientNeed for TestOrderPatient PreparationSpecimen CollectionLab ReceiptAnalysisResult VerificationAcknowledge ResultOrder TreatmentTreatmentPreanalyticalPostanalyticalTransportto LabAnalyticalProcessingFishbone Diagram from CLSI EP23Refer to Appendix A in CLSI EP18 for more comprehensive list of error sourcesSources of Laboratory ErrorTest System:Reagent contamination,deterioration,lot variationReaction fluctuationsInadequate samplingImproper or loss of calibrationElectronic or mechanical failurePower supplyEnvironment:Temperature and airflowHumidityLight intensityAltitudeOperator:Improper specimen prep,handlingIncorrect test interpretationFailure to follow test system instructionsCLIA Interpretive Guidelines for Laboratories.Appendix C,Subpart K.493.1256 Standard:Control Procedures.Interpretive Guidelines 493.1256(a)(c).http:/www.cms.gov/Regulations-and-Guidance/Legislation/CLIA/Interpretive_Guidelines_for_Laboratories.html 33Risk ManagementHolistic or global approach to quality assurance incorporating preanalytic,analytic and postanalytic phases of testingEvery instrument or device is differentHazard analysis and mitigationHazard analysis defines the sources of potential error for an instrument or device and a means of detecting or preventing the error(mitigation)34Manufacturer Checks Alternative QCSome devices have internal checks which are performed automatically with every specimen:Development of a line(Pregnancy test,Occult blood)Sensor signal(blood gas analyzer,clots)Flow resistance and liquid sensors(clots or bubbles in chemistry and hematology analyzer pipettes)Other checks engineered into instrument:Barcoding of reagent expiration dates(prevents use)Lockout features that require successful QCDisposable analyzer cuvettes/pipette tips(carry-over)Temperature indicator in shipping carton35QC and Risk ManagementAnalyzerReagentFluidics,pipetting,electronics,motorsSome internal checks detect mechanical and electronic failuresChemistry of reactionIntricately linked with the analyzerSusceptible to environment effects36QC and Risk ManagementTwo levels of QC each day,detects errors from many sources Analyzer(pipets,mechanical,electrical)Reagent(storage,drift)Operator(calibration,dilution)Environment(reagent and sample)Automated analyzers have many parts and sources of error,not all of which are detected by internal checks.QC does a good job of detecting systematic errors that persist in time,but may fail to detect random errors occurring with single samples.Random errors,like hemolysis requires serum indices on chem analyzer,visual sample inspection and/or phlebotomist training for sample collection issues37Point of Care QC and Risk ManagementDeviceTest CartridgeReads test cartridge signalInternal electronic checks maintain reader within narrow specificationsChemistry of reactionContains fluidics,calibrant,internal QC38QC and Risk ManagementDeviceOnly reads signalElectronics check environment(temp)and device integrityLocks out testing when outside specificationsTest CartridgeActs as the analyzerRisk from environment and operator effectsQC on cartridge evaluates chemistry with each testAdditional control processes for sample and for operator technique39QC and Risk ManagementQC is expensive,consumes reagent and labor without producing results that can be billed.The presence of engineered control processes on newer POCT devices raise the question of when and how these controls can substitute for two levels of liquid QC?How to best control unit-use POCT devices?Lab Director must balance requirements for QC(2 levels/day)against cost and availability of alternative controls within the test system Risk management and walking through the testing process to identify hazards and sources of error can help labs identify the right balance of liquid QC with engineered-built in control processes on the devicesIndividualized Quality Control PlanIndividualized Quality Control PlanRisk AssessmentQuality Control PlanQuality Assessment 40CLIANew IQCPCLIA,CAP and Joint Commission RequirementsTwo levels of liquid QC required each day of testingORLaboratory develops an Individualized Quality Control Plan(IQCP):Balance built-in control processes with liquid QCReduce frequency of liquid QC to minimum recommended by manufacturerMaximize clinical outcome,available staff resources and cost effectiveness in the labConsiders the laboratory process for testing and risk of errors at each step of the testing process!41What Have