Quality Assessment Flashcards
Ensures quality results by closely monitoring PRE-ANALYTICAL, ANALYTICAL, POST-ANALYTICAL
Quality assessment/ Quality Assurance
Primary Goal of Quality Assurance/Quality Assessment
Ensure quality service and products to customers
Everything precedes test performance:
- Test Ordering
- Specimen Collection
- Patient Preparation
- Patient Identification
- Specimen Transport
- Specimen Processing
Pre-analytical
Everything related to assay
- Test analysis
- QC
- Calibration
- Preventive Maintenance
Analytical
Everything that comes after the test analysis
- verification of calculation & reference ranges
- review of results
- notification of critical values
- result reporting
- test interpretation by physician
- follow-up patient care
Post-Analytical phase
World largest developer and publisher of International standards
International Organization for Standardization (ISO)
Use by Medical Laboratories in developing their quality management systems and assessing their own competence, use by ACCREDITATION BODIES in confirming or recognizing the competence of medical laboratories
ISO 15189: 2007
The Joint Commission previously known as
JCA-HO
Joint Commission on Accreditation of Healthcare Organization
Aside from TJC itself, laboratory are mandated to be accredited with (2)
COLA
Commission on Office Laboratory Accreditation
CAP
College of American Pathologist
TJC announced PPR which is required for laboratory accreditation program; PPR is also known as
Periodic Performance Review
Part of Analytical Phase of quality assurance
system ENSURING DAILY ACCURACY AND PRECISION IN LABORATORY
Quality Control
Intralab/Internal QC
Sample that is chemically and physically similar to UKNOWN specimen; Tested in same exact manner
Control
Monitors precision of test system
Control
For non-waived quantitative test, CLIA requires at least ___ levels id controls each day
2
For qualitative test, _____ and ____ must be included in the run
Positive and Negative control
Testing control not built into the system
External EC/Interlab QC
Term is also used for QC extends beyond Lab; Proficiency Testing Program
External QC/Interlab
Long term accuracy of analytical Method
External QC/ Interlab QC
Gold Standard of External QC/Interlab QC
College of American Pathologists Proficiency Program (CAP)
Electronic, Internal, procedural controls that are built into test systems
Internal Monitoring System
Labs may reduced frequency of testing External QC for certain test system if they can demonstrate a CMS-approved QC evaluation that test is STABLE
Equivalent QC
CMS stands for
Center for Medicare and Medicaid Services
These are the preferred type of control but is prone to biohazard cautions
Human control materials
Instead of Human Control Materials, it is use since it is free from biohazard cautions
Bovine Control Material
Bovine Control Materials is used preferred control but cannot be used to (3)
Immunochemistry
Dye-binding
Bilirubin assays
Reconstitution is required to avoid incorrect control values
Lyophilized Control Materials
Do not require reconstitution but may have different characterization compared to actual patient specimens
Stabilized Frozen Controls
Characteristics of a Ideal Control Materials
- Resembles Human sample
- Inexpensive and Stable
- No matrix effects
- No communicable disease
- With known analyte concentration
- Convenient packaging (Storage and dispensing)
Process of testing and adjusting analyzer’s readout to establish correlation between MEASURED and ACTUAL CONCENTRATION
Calibration
Reference material WITH KNOWN CONCENTRATION of analyte
Calibrator
Previosly known as STANDARD
Calibrator
It is a substance programmed in the computer’s analyzer for calculating concentration of UNKNOWNS
Calibrator/Standard
Testing of Materials of Known Concentration
- Calibrators
- Control
- Proficiency testing samples
- Patient with known values
TO ENSURE ACCURACY OF RESULT
Calibration Verification
Calibration Verification test how many levels?
3
High
Midpoint
Low
Calibration Verification is required to have every
- every 6 months
- change in # of reagent slot
- preventing preventive maintenance/repair
- controls are out of range
Statistical parameters describing spread of data
Measure of dispersion
Measure of Dispersion includes (4)
Mean
Range
Standard Deviation
Coefficient of Variance
Difference Between highest and Lowest in data set
Range
Sum of all observations divided by number of observations. AVERAGE of all observations
Mean
Statistical expression of dispersion of values around the mean.
Standard Deviations
Standard deviation minimum requirement of values
20
Standard deviation as percentage
Coefficient of Variation
The higher the CV; the ____ the precision
Lower
Population Probability Distribution that is SYMMETRIC about the Mean
Gaussian Curve (Bell-shaped curve)
Gaussian Curve (Bell-shaped curve)
- Values fall within + 1SD
68%
Gaussian Curve (Bell-shaped curve)
- Values fall within + 2SD
95.5%
Gaussian Curve (Bell-shaped curve)
- Values fall within + 3SD
99.7%
GUASSIAN Bell-shaped curved:
HAXI
Horizontal
Abscissa
X-Axis
Independent Values
GUASSIAN Bell-shaped curved:
VOYD
Vertical
Ordinate
Y-axis
Dependent Values
Calculates differences between WC result and Targeted mean.
CUSUM (Cumulative Sum Graph)
Earliest detection of Systematic Error (Shift)
CUSUM
Compare results on high and Low control serum from different lab
Youden/Twin plot
Most widely used; graphic representatio of acceptable limits of variation in the results of analytical method
Easily identifies random and systematic errors
Shewhart-Levey Jenning Chart
Range within which control values must fall for assay to be CONSIDERED VALID
control limits
Control result outside established limits
Outliers
6 consecutive control values on the Same side of Mean
Shift
Sudden/Abrupt change causes
Shift
Shift is due to
Improper Calibration
6 consecutive control values in decreasing or Increasing side of mean
Trend
Gradual loss of reliability
Trend
Main cause of Trend
Reagent Deterioriation
Unpredictable, Indeterminate, IMPRESICION
Random Error
Error that doesn’t occur on regular pattern due to ENVIRONMENT and Operator
Random Error
Control values that exceeds in Random Error
R4s, 13s
Determinate, Predictable, INACCURACY
Systematic error
Recurring error inherent in test procedure, CONSISTENTLY in one direction
Systematic Error
Indicated by TREND or SHIFT ON Levey-Jennings
Systematic Error
Rejection of Run because QC results indicate problem when none is present
False Rejection
If a violation of a westgard rule occurs, actions to take are:
- accept result when 12s = warning
- Reject result if westgard rule is violated
- Increase retesting range if either a warning or mandatory rules are violated
How close measurement is to true value
Accuracy
Reproducibility. How close results are when same sample is tested multiple times
Precision
Range of values over which lab can verify accuracy of test system; Also known as LINEARITY
Reportable Range
Formerly called as NORMAL VALUES. Can very for different patient population (age, gender, race)
Reference Interval
Number of healthy individuals needed to established Reference interval
120 healthy individuals
- Detection Limit
- Lowest Concentration of substance is detected
- Screening Test
- Decreased False negative
Analytical Sensitivity
- Ability of Method to detect only the desire substance/analyte
- Increased specificity; Decreased False Positive ; Decreased cross-reactivity
Analytical Specificity
Pos result in patient who has disease
True Positive
Neg result who does not have disease
True Negative
Positive result who does not have disease
False Positive
Negative Result who does have the disease
False Negative
% population with the disease with (+) result
Diagnostic Sensitivity
% population without the disease with (-) result
Diagnostic Specificity
% of time that the (+) result is correct
Positive Predictive Value
% of time that the (-) result is correct
Negative Predictive Value
proportion of cases with a SPECIFIC DISEASE that give a POSITIVE result
Sensitivity
proportion of cases WITHOUT SPECIFIC DISEASE that give a NEGATIVE result
Specificity
test indicates the number of patients with an abnormal Test result who do have the disease; compared with all patients with an abnormal result
Positive Predictive Value
test indicates the number of patients with an Normal result (negative) who do not have the disease; compared with all patients with a normal test (negative) result
Negative Predictive Value
Monitoring and Diagnosing of Disease (4)
- Diagnostic Sensitivity
- Diagnostic Specificity
- PPV
- NPV
Study to verify accuracy of new methods
Correlation study
Individuals needed for Correlation Study
40 patients samples
Perfect correlation is straight line passing through 0 at ___ angle
45 deg angle
Correlation Study Result:
0 =
+1 =
>0.95 =
0 = No correlation
+1 = Perfect correlation
>0.95 = Excellent correlation
Schedule of maintenance to keep equipment in peak operating condition.
Preventive maintenance
Procedures specified by manufacturer to evaluate critical operating characteristics of test.
Functional check
testing only those who are at high risk for exposure and for those who have symptoms
Targeted testing
Comparison of patient with previous results.
Delta check
Test results that indicates POTENTIALLY LIFE-THREATENING SITUATION
Critical Values
Critical Values includes
Glucose
Na
K
Total CO2
Calcium
Magnesium
Phosphorus
Total Bilirubin (neonates)
Blood gases
In cases of Critical values, patient care personnel must be NOTIFIED _____
IMMEDIATELY
The joint commission requires _____ policy incases of Critical values.
Read-back policy
- person receiving critical values must record and read back patient’s name and critical values.
CLIA requires documentation of competency assessment on HIRE AT 6 MONTHS AND THEN ANNUALLY
Personnel competency Assessment
Testing of unknowns submitted by OUTSIDE AGENCY e.g CAP
Proficiency Testing
