QUALITY CONTROL Flashcards
CLINICAL COMES FROM THE GREEK WORD “KLINE” WHICH MEANS?
BED
SEVEN INDEPENDENT BASE UNITS REPRESENTED BY A SYMBOL
SYSTEME INTERNATIONALE
3 CLASSES OF SI UNITS
- BASE
- DERIVE
- SUPPLEMENTAL
RECOMMENDED UNIT FOR REPORTING OF ANALYTES
MOLES OF SOLUTE/ VOLUME OF SOLUTION (MOLARITY)
IT IS RETAINED FOR MEASUREMENT OF HYDROGEN ION CONCENTRATIONS
PH SCALE
A SYSTEM THAT ENSURES THE ACCURACY AND PRECISION IN THE LABORATORY
QUALITY CONTROL
PROCESS OF ENSURING ANALYTICAL RESULTS ARE CORRECT BY TESTING KNOWN SAMPLES THAT RESEMBLE PATIENT SAMPLES
QUALITY CONTROL
ABILITY TO MEASURE THE SMALLEST CONCENTRATION OF INTEREST
SENSITIVITY
ABILITY TO MEASURE ONLY ANALYTE OF INTEREST
SPECIFICITY
NEARNESS OR CLOSENESS OF VALUE
ACCURACY
METHOD TO GIVE REPEATED RESULTS
PRECISION
DEGREE OF METHOD THAT IS EASILY REPEATED
PRACTICABILITY
MAINTAIN ACCURACY AND PRECISION DURING ANY CHANGES
RELIABILITY
TO TEST THOSE WHO HAVE DISEASE AD TEST POSITIVE
DIAGNOSTIC SENSITIVITY
TO TEST THOSE WHO HAVE NOT DISEASE THAT TEST NEGATIVE
DIAGNOSTIC SPECIFICITY
KINDS OF QUALITY CONTROL
- INTRALAB
2. INTERLAB
IT INVOLVES CONTROLS WITH PATIENT SAMPLES
INTRALAB
DETECTS CHANGES BETWEEN PRESENT AND STABLE OPERATION
INTRALAB
IT IS IMPORTANT FOR DAILY MONITORING OF ACCURACY AND PRECISION
INTRALAB
DETECTS BOTH RANDOM AND SYSTEMATIC ERROR
INTRALAB
INVOLVES PROFICIENCY TESTING WITH UNKNOWN CONCENTATION
INTERLAB
IT IS IMPORTANT FOR LONG TERM ACCURACY OF ANALYTICAL METHODS
INTERLAB
IT INDICATES THAT THE LABORATORY IS NOT IN AGREEMENT WITH THE REST OF LABORATORIES WITHIN THE PROGRAM
DIFFERENCE >2
OBJECTIVES OF QUALITY CONTROL
- STABILITY OF MACHINE
- QUALITY OF REAGENTS
- TECHNICAL ERROR
IDEAL QC MATERIAL
- RESEMBLES HUMAN SAMPLE
- INEXPENSIVE AND STABLE
- NO COMMUNICABLE DISEASES
- NO MATRIX EFFECTS
- WITH KNOWN ANALYTE
- CONVENIENT PACKAGING
RECOMMENDED NUMBER OF DAYS TO ANALYZE NEW LOT OR NEW INSTRUMENTS
5 AND 20 DAYS
IT IS CALCULATED FROM THE MEAN AND SD
CONTROL LIMITS
BOVNE-BASED QC MATERIAL ARE NOT FOR
BILIRUBIN
IMMUNOCHEMISTRY
DYE-BINDING
IT IS A RESULT OF IMPROPER PRODUCT MANUFACTURING
MATRIX EFFECT
THIS IS MORE EXPENSIVE BUT CAN BE USED AS EXTERNAL CHECKS FOR ACCURACY
ASSAYED CONTROLS
IT IS PRESENT IN ALL MEASUREMENTS DUE TO CHANCE
RANDOM ERROR
- BOTH POSITIVE AND NEGATIVE
- BASIS FOR VARYING DIFFERENCES BETWEEN REPEATED MEASUREMENTS
RANDOM ERROR
ERROR TAHT INFLUENCES OBSERVATIONS IN ONE DIRECTION CONSISTENTLY
SYSTEMATIC ERROR
- EITHER POSITIVE OR NEGATIVE BIAS
- MEASURE OF AGREEMENT BETWEEN MEASURED QUANTITY AND TRUE VALUE
SYSTEMATIC ERROR
DIFFERENCE BETWEEN TARGET VALUE AND ASSAY VALUE
INDEPENDENT SAMPLE CONCENTRATION
CONSTANT ERROR
CONSTANT DIFFERENCE BETWEEN COMPARATIVE AND TEST METHOD REGARDLESS OF CONCENTRATION
CONSTANT ERROR
GREATER DEVIATION FROM TARGET VALUE DUE TO HIGHER SAMPLE
PROPORTIONAL/SLOPE/PERCENT ERROR
TEST METHOD AND COMPARATIVE METHOD ARE PROPORTIONAL TO ANALYTE CONCENTRATION
PROPORTIONAL/SLOPE/PERCENT
HIGHEST FREQUENCY OF CLERICAL ERROR
HANDWRITTEN LABELS AND REQUEST FORMS
IT IS THE FIRST STEP IN METHOD EVALUATION THAT ESITIMATES RANDOM STUDY
PRECISION STUDY
NONLAB PERSONNEL WERE RESPONSIBLE FOR ___ OF THE ERRORS IN LAB RESULTS
29%
ASSOCIATED WITH NORMAL OR SYMMETRICAL DISTRIBUTION
MEANS
AN INDEX OF PRECISION
COEFFICIENT OF VARIATION
IT IS A MEASURE OF VARIABILITY
VARIANCE
ARE USED TO COMPARE THE MEANS OR SD OF 2 GROUPS
INFERENTIAL STATISTICS
DETERMINE THE DIFFERENCE BETWEEN MEANS OF 2 GROUPS
T-TEST
DETERMINE THE DIFFERENCE BETWEEN SD OF 2 GROUPS
F-TEST
DIFFERENCE BETWEEN DATA POINT AND MEAN DIVIDED BY SD
STANDARD DEVIATION INDEX
CHART ACCURATELY DESCRIBED BY SD AND MEAN
GAUSSIAN CURVE
CHART:
- MULTIPLE ANALYSES
- CLOSE TO MEAN
- FOCUSES ON DISTRIBUTION OF ERRORS
GAUSSIAN CURVE
IT CALCULATES BETWEEN QC RESULTS AND TARGET MEANS
CUMULATIVE GRAPH/CUSUM
CHART
- IDENTIFIES CONSISTENT BIAS PROBLEMS
- EARLIEST INDICATION OF SYSTEMATIC ERRORS
- 1(3S) RULE
CUSUM GRAPH
IN CUSUM GRAPH RESULTS ARE OUT OF CONTROL WHEN
SLOPE >45
>2. SD
CHART
- TO COMPARE RESULTS ON HIGH AND LOW CONTROL
YOUDEN/TWIN PLOT
POINTS FALLING FROM CENTER BUT WITHIN 45 DEGREE LINE
PROPORTIONAL ERROR
POINTS FALLING FROM CENTER BUT NON ON 45 DEGREE LINE
CONSTANT ERROR
MOST WIDELY USED SYSTEM IN LABORATORY
LJ CHART
- MULTIPLE RULES
- GRAPHIC REPRESENTATION OF ACCEPTABLE LIMITS OF VARIATION
LJ CHART
- CONTROL VALUES EITHER INCREASE OR DECREASE FOR 6 CONSECUTIVE DAYS
TREND
MAIN CAUSE OF TREND
DETERIORATION OF REAGENTS
CONTROL VALUES ARE ON ONE SIDE OR SIDE OF MEAN
SHIFT
IT CAUSE SHIFT IN THE REFERENCE RANGE
TRANSIENT INSTRUMENT DIFFERENCES
MAIN CAUSE OF SHIFT
IMPROPER CALIBRATION OF INSTRUMENTS
ACCEPTABLE RANGE
95% OR 2SD
DEGREE OF FLATNESS OR SHARPNESS OF VALUES HAVING GAUSSIAN DISTRIBUTION
KURTOSIS
CONTROL VALUE THAT IS A SIGN OF POTENTIAL PROBLEM
2S AND 3S
CONTROL VALUES THAT WOULD REQUIRE CORRECTIVE ACTION PLAN
3S
RECOGNIZED TAHT SIMPLE UPPER AND LOWER CONTROL LIMITS ARE NOT ENOUGH
RULE THAT INDICATES OUT OF CONTROL VALUES
WESTGARD CONTROL RULES
1(2S), 1 (3S), R(4S)
RANDOM ERRORS
2(2S)
4 (1S)
10X
SYSTEMATIC ERROR
COMBINATON OF CONTROL RULES AND CONTROL CHART
MULTIRULE SHEWHART PROCEDURE
RECOMMENDED THAT AT LEAST 40 SAMPLES AND 100 SAMPLES TO RUN RANDOM AND SYSTEMATIC ERRORS
WESTGARD
DUPLICATE ANAYLSES PERFORMED WITHIN
4 HOURS
IT CAN BE INCREASED TO DETECT SMALLER SYSTEMATIC ERRORS BY INCREASING NUMBER OF OBSERVATIONS
SENSTIVITY OF MULTIRULE PROCEDURE
SET OF CONTROL AND PATIENT SPECIMEN ASSAYED, EVALUATED AND REPORTED.
ANALYTICAL RUN
MOST COMMONLY USED PATIENT BASED QC TECHNIQUE
DELTA CHECK
TEH DIFFERENCE BETWEEN 2 CONSECUTIVE MEASUREMENTS OF THE SAME ANALYTES ON THE SAME INDIVIDUAL
DELTA CHECK
USED TO MEASURE SYSTEMATIC ERRORS TAHN THE ANALYTE
INTERFERENCE EXPERIMENTS
WHAT ARE THE INTERFERENCES
HEMOGLOBIN LIPIDS ANTICOAGULANTS BILIRUBIN PRESERVATIVES
MEASURED CONCENTRATION = ACTUAL CONCENTRATION WITHOUT MODIFICATION OF METHOD
LINEAR RANGE OR DYNAMIC RANGE
DETECTS SAMPLE CONTAMINATION, INADEQUATE VOLUME, SUDDEN PROBLEM WITH METHOD, INCORRECT RECORDING
PHYSIOLOGIC VALUE OR ABSURD VALUE
MOST COMMONLY USED POCT
PORTABLE WHOLE BLOOD GLUCOSE METERS
ENVISIONED AS A TRIPOD WITH PROGRAM DEVELOPMENT, ASSESSMENT AND MONITORING
QUALITY ASSURANCE
THESEA RE ALL SYSTEMATIC ACTIONS FOR ADEQUATE CONFIDENCE TAHT LAB SERVICES WILL SATISFY MEDICAL NEEDS
QUALITY ASSURANCE
TO DELIVER QUALITY SERVICES AND PRODUCTS TO CUSTOMERS
PRIMARY GOAL OF QUALITY ASSURANCE
IT WILL SHOW WHETEHER A METHOD MEASURES ALL ANALYTES OR ONLY PART OF IT
SYSTEMATIC ERROR
RECOVERY EXPERIMENT
5 FACTORS WHEN ESTABLISHING REFERENCE INTERVALS
- COMPOSITION OF REFERENCE POPULATION
- CRITERIA
- PHYSIOLOGIC AND ENVIRONMENTAL CONDITIONS
- SPECIMEN COLLECTION
- METHODS
IT IS NEEDED TO DERIVE RELIABLE ESTIMATES OF REFERENCE INTERVALS
120 INDIVIDUALS
IT IS ONLY THE NEEDED SAMPLE IF LABORATORIAN DETERMINES TEST INSTRUMENT AND SUBJECT ARE THE SAME WITH MANUFACTURER’S INSERT
20 INDIVIDUALS