BLD 313 EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED
bias
Systematic error, based on accuracy, always adding the same amount error
- distance between true value and mean
random error
is precision based, due to machinery
- it is + or - 2SD
systematic error
based on accuracy, bias, always adding the same amount error
total error
also known as the observed error, = systematic error + random error
allowable error
requirement: observed error < allowable error
- the determination of the allowable error is:
1. governments (CLIA and Base on consensus, peer group mean and SD)
2. Medically allowable error
which criteria are used for allowable error
,Allowable error will follow the stricter limit if government and medically allowable error
are different
- CLIA :
+ usually the widest degree of allowable error
+ all assays must meet this criteria
- medically allowable
+ different standards for different certifying agencies
+ if no published allowable is available:
++ internal analytic error (if only a few labs are performing this test)
++ consensus (if many labs are performing this test)
how do you express allowable error
- percentage of a target value: coefficient of variation (%CV)
- absolute concentration
- standard deviation and target for analytes with no published allowable error
medically allowable error
medically useful degree of accuracy and precision
- based on:
+ normal reference range
+ intraindividual variation
+ difference between normal and disease distribution
,+ established by professional societies/ certifying agencies
no government involvement
GOOGLE: Used here to indicate errors that, when added to the inherent imprecision
and inaccuracy of a measurement procedure, cause the quality requirement to be
exceeded.
what are the professional societies/ certifying agencies
CAP, COLA, JC, and Proprietary organization
- there are different standards for different certifying agencies
consensus error
compare your results with your peer labs. (if many labs are performing this test)
target value
Used in proficiency testing (external QC) to designate the correct value, usually
estimated by the mean of all participant responses, after removal of outliers, or by the
mean established by definitive or reference methods.
what is the quality control process
- internal QC
- Preparation of QC material
Outline the procedure used to prepare quality control material.
Do this if this is rare test or unknown range:
1. pool large quantity of material
2. immediately analyze to samples (gets rid of some random error)
3. aliquot into individual vials
, 4. store
5. establish temporary QC values from the 40 results
- test 2 vials (controls) in duplicate for next ten days: check stability in storage
- temporary target (checking accuracy)
- %CV expressed as allowable error
6. continue testing on a scheduled basis
- data accumulation n=200
- duration of 2 months
8. establish final QC value
- final target value
- %CV expressed as allowable error
Discuss the protocol followed in an internal quality control program.
Internal QC:
- evaluation of a single specimen at few different levels on a scheduled basis
- use a known range of acceptable value
what is the concentration of quality control material
- concentration of QC material: at least 2 levels (+ or - SD) of QC, depends on analytes
+ normal
+ abnormal high
+ abnormal low
what is the frequency of monitoring controls
- minimum once per day
- more freq. if subject to rapid drift
COMPLETE SOLUTIONS VERIFIED
bias
Systematic error, based on accuracy, always adding the same amount error
- distance between true value and mean
random error
is precision based, due to machinery
- it is + or - 2SD
systematic error
based on accuracy, bias, always adding the same amount error
total error
also known as the observed error, = systematic error + random error
allowable error
requirement: observed error < allowable error
- the determination of the allowable error is:
1. governments (CLIA and Base on consensus, peer group mean and SD)
2. Medically allowable error
which criteria are used for allowable error
,Allowable error will follow the stricter limit if government and medically allowable error
are different
- CLIA :
+ usually the widest degree of allowable error
+ all assays must meet this criteria
- medically allowable
+ different standards for different certifying agencies
+ if no published allowable is available:
++ internal analytic error (if only a few labs are performing this test)
++ consensus (if many labs are performing this test)
how do you express allowable error
- percentage of a target value: coefficient of variation (%CV)
- absolute concentration
- standard deviation and target for analytes with no published allowable error
medically allowable error
medically useful degree of accuracy and precision
- based on:
+ normal reference range
+ intraindividual variation
+ difference between normal and disease distribution
,+ established by professional societies/ certifying agencies
no government involvement
GOOGLE: Used here to indicate errors that, when added to the inherent imprecision
and inaccuracy of a measurement procedure, cause the quality requirement to be
exceeded.
what are the professional societies/ certifying agencies
CAP, COLA, JC, and Proprietary organization
- there are different standards for different certifying agencies
consensus error
compare your results with your peer labs. (if many labs are performing this test)
target value
Used in proficiency testing (external QC) to designate the correct value, usually
estimated by the mean of all participant responses, after removal of outliers, or by the
mean established by definitive or reference methods.
what is the quality control process
- internal QC
- Preparation of QC material
Outline the procedure used to prepare quality control material.
Do this if this is rare test or unknown range:
1. pool large quantity of material
2. immediately analyze to samples (gets rid of some random error)
3. aliquot into individual vials
, 4. store
5. establish temporary QC values from the 40 results
- test 2 vials (controls) in duplicate for next ten days: check stability in storage
- temporary target (checking accuracy)
- %CV expressed as allowable error
6. continue testing on a scheduled basis
- data accumulation n=200
- duration of 2 months
8. establish final QC value
- final target value
- %CV expressed as allowable error
Discuss the protocol followed in an internal quality control program.
Internal QC:
- evaluation of a single specimen at few different levels on a scheduled basis
- use a known range of acceptable value
what is the concentration of quality control material
- concentration of QC material: at least 2 levels (+ or - SD) of QC, depends on analytes
+ normal
+ abnormal high
+ abnormal low
what is the frequency of monitoring controls
- minimum once per day
- more freq. if subject to rapid drift
