QC Flashcards
Quality Management
Organizational Level
Processes that affect the quality of laboratory test results
12 major components (QSE)
Update processes
SOP review
12 QSE
Quality Management
Quality Improvemt
Organization and Structure
Personnel Management
Information Management
Occurance Management
Process Control
Service and Satisfaction
Assessment
Documents and Records Management
Equipment Management
Purchasing and Inventory
Facilities and Safety
Quality Assurance
Management/Supervisor level
Activities implemented so quality requirements are fulfilled - ensures reliability of test results.
All activities related to specimen testing
Pre-analytical, Analytical, Post-analytical
Pre-analytical variables
Test ordering
Patient preparation and ID
Specimen collection
Transport of specimen
Handling of specimen before testing
Analytical variables
QC procedures for each test method
Use of QC samples along with pt samples
Post-analytical variables
Turn-around-time
Reporting of results
Quality Control
Individual Level
Monitoring of a test procedure
Ensures results are VALID, ACCURATE, PRECISE
Alerts technologist of a problem
Accuracy
Reliability
Closeness in which a result checks with the true value
4 assessments of Accuracy
- Running QC sample with known amount of substance - compared to true value
- Comparison of results from a reference method
- Comparison of results to reference laboratory
- Use of recoveries (not used in Hem) - known substance is added to a solution, ran, determine how much substance is recovered
Reference method - specific for analyte, accurate, gold standard
Precision
Reproducibility
Closeness of results between several repeats
Coefficient of Variation
Standard Deviation
Qualities of QC material
- Similar composition and form to unknown samples (whole blood)
- Analyzed in same manner as unknowns
- Stable (saves money and time)
- Known value established by manufacturer
When do you use Coefficient of Variation?
Comparison of two different assays
Test precision of tests with different concentration units
Methods with different means
Establish limits of allowable variation (at diff conc ranges)
Primary Standard
Reference material with known [analyte]
Used to calibrate instrument or prepare standard curves
Secondary Standard
Reference material [analyte] was determined by reference to primary method
Calibrator
Cell suspension with known parameters
Assigned value has been tested by multiple reference labs and reference methods
Cyan-methemoglobin standard
Adjust parameters on auto analyzer
Neither precision or accuracy - instrument adjustment
Westguard QC rules
12S - single control value +/-2SD (random, systmatic) WARNING RULE
22S - two consequtive control values outside +/-2SD (systematic) REJECTION RULE
13S - single control value is outside +/-3SD (random) REJECTION RULE
R4S - range between two control value within a run is >4SD; one exceeds +2SD while next exceeds -2SD (random) REJECTION RULE
41S - four consequtive control values exceed 1SD on same side (systematic) REJECTION RULE
10X - ten consequtive control values fall on same side of mean (systematic) REJECTION RULE
41S, 10X - trend is starting/established
Systematic Error
Regular and deteminate (measurable)
Loss of accuracy
Change in mean (not SD)
Result in shifts/trends
Contant systematic error
same direction, same magnitude
Proportional systematic error
increase in magnitude and concentration of substance increases
Sources of SYSTEMATIC ERROR
Change of reagent/calibrator lot number
Deteriorationg or imporoperly prepared reagents
Imporoper pipette calibration (alters sample volume)
Deterioration of light source (photometric)
Deterioration of QC material
Changed incubator temperature
Random Errors
Accidental, indeterminate, lack defined pattern
Decrease precision, large SD
can be detected via Delta Checks
Sources of RANDOM ERROR
Bubbles (reagent, line)
Inadequate mixing
Unstable temperature, electrical source
Individual operator variation (pipetting)
Delta Check
Compares patient recent result with past one
> 30% change
Add comment to result
Recollection may be needed
Bull’s Moving Averages
Detect/monitor instrument issues
Shift
Bull’s Moving Averages Principle
RBC indices contant in a population
Data is compared between batches in a population
Action with critical results
Review testing conditon
Previous criticals?
Sample integrity
- confirm result
Phone pt location/physician
-document phone call
