QC 101

• What is Laboratory Quality?

  Accuracy, reliability, and timeliness. Lab results must be accurate as possible.
• What is quality assurance?

  QA in the lab is all the things we do to ensure quality results.
• ISO Document that applies to the medical Lab is ISO 15189
• The Lab:

  Organization, Customer Focus, Facilities and safety, Personnel, Purchasing and Inventory, Equipment.
• The Work:

  Process Management, Documents and records, Information management.
• Performance:

  Nonconformance Management, Assessments, Continual Improvement. (Reflecting on self performance).
• Pre-analytic


  Test order, sample collection, transport, receipt and process
• Analytic

  Testing
• Post-analytic


  reporting, sample archiving
• Sensitivity

  Measures low amount of component, few false negatives if high sensitivity, Positive controls in low amounts.
• Specificity

  Specific- measures one component only, no false positives, uses negative controls.
• Report sent to wrong location

  Post-analytical
• QC not within range

  Analytical
• Mislabeled specimen

  Pre-analytical
• CV= SD/ Mean divided by 100


  Always to 1 decimal place and in percent
• Precision


  reproducibility of a result. Ex hitting the same spot on the target.
• Accuracy


  The correctness. Ex. hitting the center of the target.
• Systemic error

  Change in accuracy, affect all results until the error is fixed.
• Random error

  Change in precision, no prediction, one off.
• Population

  large body of data- should be random and represent any part of the population.
• Calibrator

  Similar to standard, has more than one analyte, used to correct analytical procedure.
• Standard

  A solution having known concentration of a single analyte.
• Control

  A solution that contains the same constituents as those being analyzed in the patient sample. Used to test if our analytical system is giving accurate results or not.
• The lower the CV the more precise.
• Acceptable CV

  Manual methods= less than or equal to 10.0%

  Instrumental methods= less than 3.0%
• Normal Distribution

  1SD- 68%

  2SD- 95%

  3SD- 99.7%
• Reference Range

  Range of results for clinically healthy people.
• Control range

  The acceptable range of a known control sample for an analyte in order to monitor the precision and accuracy of our analytical system.
• New lot # means calibration time
• Quantitative analysis

  The control is a sample that has known values. Used for accuracy and precision.
• Qualitative analysis


  Provide positive vs negative or reactive vs non-reactive. Known as screening tests- Ex. covid or pregnancy test.
• 1 in 20 control values may fall outside of the 2SD range.
• Trend

  Gradual loss of reliability. Usually subtle. Deterioration.
• Shift

  Abrupt change, a sudden or dramatic positive or negative change.
• Always run QC after calibration
• Linearity range

  If a sample is above linearity range or too high to be run on the analyzer, it can be diluted.
• Linearity (dynamic range)

  The limit of what the analyzer can detect on a test.