Laboratory Internal Quality Control presentation master revision, 2014

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Short presentation about using internal quality control material in clinical laboratory to ensure analytical quality laboratory results for the sake of better patient care and minimizing errors in diagnosis, management, and follow up.

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Laboratory Internal Quality Control presentation master revision, 2014

  1. 1. Dr. Adel A. Elazab Associate Professor of Clinical Pathology Faculty of Medicine Ain Shams University, Cairo, Egypt
  2. 2. Internal Quality Control Dr. Adel A. Elazab 2
  3. 3. Internal Quality Control Dr. Adel A. Elazab 3 QUALITY ASSURANCE PROGRAMME ! Internal Quality Control (IQC) Procedures ! External Quality Assessment (EQA) ! Quality Management
  4. 4. Internal Quality Control Dr. Adel A. Elazab 4 Internal Quality Control (IQC) Procedures ⇒ Done during daily routine work ⇒ Provides an immediate control ⇒ Errors are corrected immediately ⇒ Routinely collect and analyze data from every test run or procedure Why do we need Internal Quality Control? ! Ensure that test results are reliable ! Ensure that test results are reproducible ! Control quality of daily routine work
  5. 5. Internal Quality Control Dr. Adel A. Elazab 5 Internal Quality Control Monitoring quality of laboratory testing, accuracy and precision of laboratory results
  6. 6. Internal Quality Control Dr. Adel A. Elazab 6 Precision and Accuracy • Precise and Inaccurate • Precise and Accurate
  7. 7. Internal Quality Control Dr. Adel A. Elazab 7 Precision and Accuracy • Imprecise and Inaccurate • Imprecise and ?? Accurate
  8. 8. Internal Quality Control Dr. Adel A. Elazab 8 Internal Quality Control • It ensures continual check that the established reliability of the laboratory’s work does not fluctuate and that reports are validated before they are released. • It is based on monitoring the procedures which are actually used for the tests in the laboratory. It includes: · Control charts with tests on control materials · Duplicate tests on all specimens or on a proportion of the specimens · Delta check, comparing current test results with previous results · Consistency of mean values of patient data
  9. 9. Internal Quality Control Dr. Adel A. Elazab 9 QC Quantitative Tests • Use 2-3 levels of controls covering the medical decision points • At least 20 control values over a period of 20-30 days for each level of control • Perform statistical analysis • Develop Levey-Jenning chart • Run -regularly- with patient samples • Monitor control values on chart using Westgard rules • Take immediate corrective action, if needed • Record actions taken (if any)
  10. 10. Internal Quality Control Dr. Adel A. Elazab 10 QC Quantitative Tests • QC material must be available in large quantities stored in small aliquots (Ideally should last for at least 1 year) • Always consider as Biohazardous • Requires very accurate reconstitution if needed • Always deal with and store as recommended by manufacturer
  11. 11. Internal Quality Control Dr. Adel A. Elazab 11 Analysis of Control Materials • Need data set of at least 20 points obtained over 20-30 days better by different operators in different times of day • Calculate mean, standard deviation, Coefficient of variation and determine target ranges • Develop Levey-Jenning charts • Plot –on the chart- control values each run/ day • Make decisions regarding acceptability of run using Westgard rules • Monitor over time and at defined intervals
  12. 12. Internal Quality Control Dr. Adel A. Elazab 12 1. 192 mg/dL 2. 194 mg/dL 3. 196 mg/dL 4. 196 mg/dL 5. 160 mg/dL 6. 196 mg/dL 7. 200 mg/dL 8. 200 mg/dL 9. 202 mg/dL 10.255 mg/dL 11.204 mg/dL 12.208 mg/dL 13.212 mg/dL Calculation of the Mean: Outliers
  13. 13. Internal Quality Control Dr. Adel A. Elazab 13 Levey-Jennings Chart Calculate the Mean and Standard Deviation; Record the Mean and +/- 1,2 and 3 SD Control Limits 80 85 90 95 100 105 110 115 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Day Mean +1SD +2SD +3SD -1SD -2SD -3SD
  14. 14. Internal Quality Control Dr. Adel A. Elazab 14 Levey-Jennings Chart - Record and Evaluate the Control Values 80 85 90 95 100 105 110 115 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Day Mean +1SD +2SD +3SD -1SD -2SD -3SD
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  16. 16. Internal Quality Control Dr. Adel A. Elazab 16 Findings Over Time • Ideally should have control values clustered around the mean (+/-2 SD) with little variation in the upward or downward direction • Imprecision = large amount of scatter around the mean. Usually caused by errors in technique • Inaccuracy = may see as a trend or a shift, usually caused by change in the testing process • Random error = no pattern. Usually poor technique, malfunctioning equipment
  17. 17. ERRORS Random Error (RE): Imprecision • Causes: 1. Pipetting error 2. Temperature error 3. Mixing defect 4. Machine need troubleshooting • Systematic Error (SE): Inaccuracy • Causes: 1. Deterioration of control material 2. Deterioration of calibrator 3. Deterioration of reagents Internal Quality Control Dr. Adel A. Elazab 17
  18. 18. Internal Quality Control Dr. Adel A. Elazab 18 Westgard Rules • Allows determination of whether an analytical run s (in control) or (out of control)
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  33. 33. Internal Quality Control Dr. Adel A. Elazab 33 Traditional Westgard Rules
  34. 34. Internal Quality Control Dr. Adel A. Elazab 34 Westgard Multirules • When you're running 2 or 4 control levels, use the rules: 13s/22s/R4s/41s/10x • When you're running 3 control levels, use a set that works for multiples of threes: 13s/2of32s/R4s/ 31s/12x
  35. 35. Internal Quality Control Dr. Adel A. Elazab 35 When a Rule is Violated • Warning rule = use other rules to inspect the control points • Rejection rule = Out of control= 1. Stop testing 2. Identify and correct problem 3. Repeat testing on pt samples and control 4. Don’t report pt results until problem is solved and controls indicate proper performance
  36. 36. Internal Quality Control Dr. Adel A. Elazab 36 When a Rule is Violated • Change one variable at a time to troubleshoot an out of control (> ±2sd) test. • The variables are usually common to all instruments or procedure systems and include the following: • 1. Try a fresh vial of QC • 2. Try a new reagent (same lot) • 3. Try a new consumable (water, part, solution, tubing) if applicable. • 4. Try a new reagent (new lot) • 5. Recalibrate (current calibrator) • 6. Recalibrate (new lot calibrator) • If a system cannot be brought into control, notify senior staff. Do not process patient samples for the test affected.
  37. 37. Internal Quality Control Dr. Adel A. Elazab 37 Overlap New Lot of Controls When changing to a new lot number of control material, ideally there should be an overlap period while the new material is being analyzed to establish the new control limits. In cases where the overlap period is not sufficient, it is possible to establish the mean value for the new control material in a short time, over say a five-day period, or to start with the manufacturer’s values. Then apply the previous estimate of SD to establish the control limits. These control limits should be temporary, until sufficient data is collected to provide good estimates of both the mean and SD of the new material.
  38. 38. Internal Quality Control Dr. Adel A. Elazab 38 Establishing the Value of the Mean for a New Lot of QC Material • New lots of a quality control material should be analyzed for each analyte in parallel with the lot of control material in current use. • Ideally, a minimum of at least 20 measurements should be made on separate days when the measurement system is known to be stable, based on QC results from existing lots. • If the desired 20 data points from 20 days are not available, provisional values may have to be established from data collected over fewer than 20 days. • Possible approaches include making no more than four control measurements per day for five different days
  39. 39. Internal Quality Control Dr. Adel A. Elazab 39 QUALITY “QUALTY IS NEVER AN ACCIDENT; IT IS ALWAYS THE RESULT OF HIGH INTETION, SINCERE EFFORTS BY ALL, INTELLIGENT AND SKILLFUL DIRECTION AND EXECUTION, IT REPRESENTS THE WISE CHOISE OF MANY ALTERNATIVES”
  40. 40. YOUR VALUABLE QUESTIONS

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