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Introduction to Quality Assurance and Quality Control

Introduction to Quality Assurance and Quality Control

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Introduction to Quality Assurance and Quality Control

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  1. Introduction to Quality Assurance and Quality Control Module 10

  2. Learning Objectives Upon completion of this lesson you will be able to: • Define: Quality Assurance, Quality Control, Quality Indicators, analytical errors, Laboratory Best-Practices, Calibrator, Controls, mean, median, mode, standard deviation, coefficient of variation, Levey-Jennings chart, Gaussian curve, Control Range, Normal or Reference Range • Describe the purpose and key components of a quality assurance program • Differentiate quality assurance from quality control

  3. Learning Objectives Upon completion of this lesson you will be able to: • Explain strategies for minimizing errors in laboratory results • Calculate the mean, standard deviation, coefficient of variation, and +(-) 3 Std Dev Range using a given set of data points • Construct a Levey-Jennings chart and plot a given set of data points

  4. What is Quality Assurance? Quality Assurance (QA) is…. A set of proactive policies and procedures ascribed to, in order to create and maintain good quality practices and therefore accurate and precise outputs (laboratory results).

  5. Definitions • Quality Control: Procedures regularly practiced throughout the laboratory to verify that procedures, practices and laboratory results are accurate and precise • Pre-analytical: processes that occur to obtain and prepare specimens before testing • Analytical: processes within the testing phase • Post-analytical: processes that take place after testing and until results are released

  6. Definitions • Certified reference material, CRM: “A reference material that has one or more values certified by a technically valid procedure and is accompanied by, or is traceable to, a certificate or other document that is issued by a certifying body.” [CLSI] • Control Material: Aqueous material with a protein base similar in composition to human plasma/serum. Can be ordered assayed (with values) or un-assayed (with no values)

  7. Definitions • Calibration.“The process of testing and adjustment of an instrument, kit, or test system, to provide a known relationship between the measurement response and the value of the substance being measured by the test procedure.” [CLSI]

  8. Definitions • Calibration verification. “The assaying of calibration materials in the same manner as patient samples to confirm that the calibration of the instrument, kit, or test system has remained stable throughout the laboratory’s reportable range for patient test results.” [CLSI] • Quality Indicators: Measures (qualitative or quantitative) that indicate the test system and lab operation are functioning as expected

  9. Definitions • Laboratory Best-Practices: Utilization of quality policies and procedures to produce the best laboratory outcomes • Process Mapping: Breaking down a process step by step to define what is done, who is responsible, and what might fail or need improvement at each step

  10. Definitions • Mean : Common expression for the mean of a statistical distribution with a discrete random variable is the mathematical average of all the terms. To calculate it, add up the values of all the terms and then divide by the number of terms. • Std Deviation: For a measurement procedure, it is generally expected that the distribution of control results will be normal or Gaussian. • Coefficient of Variation (%CV): Describes the standard deviation as a percentage of the mean, as shown in the following equation: CV = (s / m )100

  11. Definitions • Levey-Jennings Chart: • A visual graph showing control values over a period of time (usually a month) • Gaussian curve: • Statistical distribution of values around a calculated mean • normally bell-shaped

  12. Definitions • Control Range: • The accepted values of a control material • Includes a mean and +(-) 3 std dev • Normal or Reference Range: • The values of a specific analyte obtained from individuals considered to be healthy (usually 95% range)

  13. The Quality Assurance Cycle Pre-Testing Patient/Client Prep Sample Collection Personnel Competency Test Evaluations Reporting • Data and Lab Management • Safety • Customer Service Post-Testing Sample Receipt and Accessioning Record Keeping Sample Transport Quality Control Testing Testing Evaluation

  14. Purpose of Quality Assurance Benefits in the Laboratory: • Provides the highest quality results for the patient • Quality Assurance: • Assists physicians in patient diagnosis, treatment and the monitoring of treatment • Builds physician trust for the laboratory and prevents complaints - which also motivates staff • Is the most cost-effective in the long run

  15. Four Key Components of Quality Assurance • External quality assessment (EQA) • Internal quality control (IQC) • Standardization of processes and procedures (pre-analytic, analytic and post-analytic phases) • Management and 0rganization (documentation and retention of all records including monitoring Quality Indicators and corrective action).

  16. External Quality Assessment Unknown specimens provided by an outside agency and sent to laboratories for analysis to check the lab’s accuracy. Proficiency Testing • For all tests done on site • Handling rules apply

  17. Internal Quality Control • All checks and procedures a laboratory regularly carries out to ensure test results are accurate • A well functioning internal assurance scheme results in good performance in External Quality Assessment

  18. Internal Quality Control: Pre-Analytical Activities Examples: • Specimen Collection and Management

  19. Internal Quality Control: Analytical Activities Examples: • Instrument calibration • Equipment maintenance • Analysis of known test samples (QC)

  20. Internal Quality Control: Post-Analytical Activities • Examples: • i.e. crosschecking and validation of results

  21. Quality Assurance vs. Quality Control • Quality Assurance: Proactive policies and procedures ascribed to in order to create and maintain good quality practices • Quality Control: Procedures regularly practiced throughout the laboratory to verify that procedures, practices and therefore laboratory results are accurate and precise

  22. Differences in QA and QC Quality Assurance Quality Control Concerned with the product Involves evaluating a product, activity, process, or service Evaluates whether or not the end result is satisfactory • Process–oriented • Designed to make sure processes are sufficient to meet objectives • Ensures a product or service is manufactured, implemented, created, or produced in the right way

  23. Standardization of Processes and Procedures When test processes are performed the same each time, procedure errors are eliminated. This is accomplished by: SOP for all phases of testing: Pre-analytic Analytic Post-analytic

  24. Management & Organization • All QC and QA activities should be documented when done. • Corrective action, if needed, should be carried out timely and legibly documented. • Records should be reviewed regularly by the laboratory supervisor and retained within the laboratory’s organized archives for the required retention period.

  25. Analytic Errors During the testing phase errors that may occur can be detected by: • Equipment monitoring • Error codes from analyzers • Quality control sample result rejection signals using selected criteria (Westgard Rules)

  26. Data Error Flags: An example from the AMS Autolab

  27. Examples of Quality Control & Quality Assurance • Documentation of temperature control • Documentation of pipette calibration • Quality Control samples analysis • Use of Standardized procedures (SOPs) • Documentation of competency checks for staff • Documentation of preventive maintenance of equipment • Cross check and verification of lab reports


  29. Use of QC Materials • To monitor the analytical test system by running DAILY QC • Acceptance versus rejection of patient results • 2 or 3 control materials • Normal, high and/or low

  30. Post-Analytic Errors • Wrong reference ranges • Not reporting in a timely manner • Not using correct method of reporting • Not retaining record of patient results and report • Not crosschecking for transposition or clerical errors • No validation of results for illogical or incompatible results

  31. Reporting Patient Results • Use Correct Format • Proper alignment, • Placement of decimal points and zeros • Legible if handwritten • Maintain Confidentiality • Retain Records

  32. Interactive Opportunity • Who is responsible for QA and QC? • What is External Quality Assessment? • Why is this important? • How should EQA specimens be handled? • Name the aspects of the analytical testing • phase that can cause inaccurate results but • would be revealed with unacceptable QC • sample results?

  33. Lab Exercise: Quality Control and Construction of Levey-Jennings Charts

  34. Levy-Jennings Activity Objectives At the completion of this activity, you will be able to: • Perform statistical analysis on analyte values from the previous month’s control values to determine Mean, Std Dev, %CV. • Draw a Levy-Jennings chart, label the x and y axis correctly, and properly label the LJ chart for documentation and filing. • Plot current month’s values daily and evaluate LJ chart for Westgard violations, trends, shifts. • Discuss the necessity of Quality Control and how they assess precision and accuracy

  35. Gaussian Distribution

  36. Accuracy & Precision • Accuracy: The closeness of the measured result to the true value • Precision: Reproducibility or closeness of results to each other

  37. Inaccurate and Imprecise

  38. Reliability • The ability to maintain both precision and accuracy

  39. Quality Control • Quality control is used to test the analytical phase of patient testing • It is a process or system for monitoring the quality of laboratory testing, and the accuracy and precision of results

  40. Last Month’s QC Values (Glucose mg/dL) • Calculate the Mean: __________ • Calculate Std Dev: __________ • Calculate %CV: __________ • Determine + 3 SD Range: ____________ 5. Construct graph & plot all points

  41. This Month’s QC Values (Glucose mg/dL)

  42. Instrument: _________________ Test: ____________________ Units: ________Method: ____________________ Month/Year: ______________ Tech: ________ Control: ____________________ Lot #: ____________________ Exp: _________Control Mean: _______________ 1 Std Dev: ________________ -+3 SD Range: _________ + 3s(90) + 2 s (85) + 1 s (80) Mean (75 mg/dL) -1 s (70) - 2 s (65) - 3 s (60) Days

  43. This is What the Student’s LJ Chart Should Look Like: