quiz mx

  1. errors that occur in testing process may be either
    • random
    • systematic
  2. only a cause for rejection of the test run if it exceeds +2SD
    random error
  3. error is not acceptable, as it indicates some failure in the system that can and should be corrected
    systematic error
  4. examples of systematic error
    • shift
    • trend
  5. when the control is on the same side of the mean for five consecutive runs
  6. when the control is moving in one direction, and appears to be heading toward an out of control value
  7. can help distinguish between normal variation and systematic error
    levey-jennings charts
  8. in most situations, measurement uncertainty is estimated at
    95% coverage
  9. for most instances, a range of ___ is accepted as measurement uncertainty that is explained by random variation
    ± 2SD
  10. when QC sample that is used in a test run is out of the acceptable range, the run is considered to be ___________
    out of control
  11. the closeness of a measurement to its true value
  12. the amount of variation in the measurements
  13. the difference between the expectation of a test result and an acceptable reference method
  14. the reliability of a method is judged in terms of
    accuracy and precision
  15. to determine acceptable variation, the laboratory must compute the SD of the ___ values
  16. ____ of the values will fall within -1SD and +1SD of the mean
  17. ____ of the values will fall within -2SD and +2SD of the mean
  18. ____ of the values will fall within -3SD and +3SD of the mean
  19. the measurement of variation in a set of results
    standard deviation (SD)
  20. formula : SD
  21. when only one control is used, we consider an examination run to be __ if a value is within 2SD of the mean
    in control
  22. the SD expressed as a percentage of the mean
    coefficient of variation (CV)
  23. formula CV
    • CV (%) = SD x 100
    •               ------
    •               Mean
  24. used to monitor precision
  25. ideally, the value of CV should be
    less than 5%
  26. westgard rule was developed by
    James Westgard
  27. multirule system requires running two controls (or 3 controls) of different target values for each set of examinations, developing a Levey-Jennings chart for each, and applying the rules
    Westgard Rules
  28. represent the range graphically for purpose of daily monitoring
    Levey-Jennings Chart
  29. another set of rules used to avoid rejecting runs that may be acceptable
    Westgard Rule
Card Set
quiz mx