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QC > Mid 1 LO1 -LO3. 7 > Flashcards

Mid 1 LO1 -LO3. 7 Flashcards

1
Q

Why do we need to take QC 194?
3

A

quality control, management, assurance

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2
Q

laboratory quality 3 key words

A

accuracy, reliability and timeliness

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3
Q

Quality is defined as

A

excellence

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4
Q

What is Quality Assurance?

A

all the actions a laboratory takes to ensure quality results

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5
Q

laboratory errors cost in 3 things

A

time
personnel effort
poor patient outcomes

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6
Q

inaccurate results provided lead to these consequences

A
  • Unnecessary treatment
  • treatment complications
  • failure to provide the proper treatment
  • delay in correct diagnosis
  • additional and unnecessary diagnostic
    testing
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7
Q

achieving 99% level of quality =

A

accepting a 1% error rate

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8
Q

In order to achieve the highest level of accuracy & reliability it is essential to

A

perform all processes and procedures in the
laboratory in the best possible way

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9
Q

A Quality Management System for the Laboratory

is what type of method

A

A method of detecting errors at each phase of testing is needed if quality is to be assured

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10
Q

ISO standards dos what

A

groups the laboratory system into 3 categories

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11
Q

laboratory systems the 3 categories by the ISO

also called The quality assurance cycle

A

Preexamination, Examination, Postexamination

= Pre-Analytic, Analytic, and Post-Analytic processes

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12
Q

Quality system essentials : The building blocks/ 12 QSEs= how we achieve excellent performance

what are the 3 sub categories

A

The lab
The work
Performance

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13
Q

Quality system essentials : The building blocks/ 12 QCs

The lab : 6 subs

A

-Organization
-customer focus
-facilities and safety
-personnel
-purchasing and inventory
-equipment

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14
Q

Quality system essentials : The building blocks/ 12 QCs

The work: 3 subs

A

-Process management
-Documents and records
-information management

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15
Q

Quality system essentials : The building blocks/ 12 QCs

performance: 3 sub

A

-nonconformance managements
-assessments
-continual improvement

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15
Q

Quality system essentials : The building blocks/ 12 QCs

performance: 3 sub

A

-nonconformance managements
-assessments
-continual improvement

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16
Q

Quality Management System
what does it do
international vs Canada

A

= Coordinated activities to direct and control an organization with regard to quality (ISO-international, CLSI-Canada)

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17
Q

Path of Workflow: 5

A

The patient
test selection
sample collection
sample transport
repost creation

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18
Q

what is the path of workflow accessing ? important in

A

validity

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19
Q

QSEs
1. Organization

A

-must be structured
-Responsibilities, authorities
-provision of recourses
-communication

ex
following governing bodies for Structure
Quality planning - reports, improvement process
Communication -huddles, documents, reports

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20
Q

QSEs
2. Customer service

A

clinicians, patients

-customer feedback documented and analyzed
-informing costumers of changes
-costumers can email concerns
-safety alert system that both can report to

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21
Q

QSEs
3. Facilities and Safety

A

-safe working environment
-transport management
-security
-containment
-waste management
-laboratory safety
-ergonomics

ex
having safety committees and governing bodies
-biohazard safety/ disposal
-having codes in emergencies/ colors
-chemical hygiene

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22
Q

which ISO safety standards number regulates safety regulations

A

15190

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23
Q

number too make a safety issue report

A

306 655 1600

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24
Q

QSEs
4. Personnel

A
  • Human resources
  • Job qualifications
  • Job descriptions
  • Orientation
  • Training
  • Competency assessment
  • Professional development
  • Continuing education
  • SOPs (standard operating procedures)
  • Work logs
  • confidentiality
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25
Q

what does HIPA stand for

A

Health Information Protection Act

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26
Q

QSEs
5. Purchasing and Inventory

A
  • Vendor qualifications
  • Supplies and reagents
  • Critical services
  • Contract services
  • Contract review
  • Inventory management
    -documentation
  • proper returns in case of defects
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27
Q

QSEs

  1. Equipment
A
  • Acquisition
  • Installation
  • Validation
  • Maintenance- scheduled and loged
  • Calibration
  • Troubleshooting
  • Service and repair
  • Documentation/records
  • Procedures
  • Running controls

-operation life cycles
-justifying needs for equipment
-decommissioning

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28
Q

QSEs

  1. Process control
A
  • Quality control
  • Sample management
  • Method validation
  • Method verification

pre-analytic, analytic, post analytic

The phases include patient preparation and proper identification, sample collection
requirements, control samples, calibrators, reagents and equipment performance, correlation of
test results and proper entry of patient results into the computer system for the physicians.

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29
Q

how long is the turn around time

A

1 hr

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30
Q

QSEs
8. Documentation and Record Keeping

A

Laboratory information is permanent and cannot be tampered with unless signed or
initialed, therefore, record keeping is a legal responsibility under government
regulations and should be confidential, yet easily retrieved for use by the
accreditation team. As well, log books are kept for maintenance, temperatures of
fridges, water baths, incubators etc. for specific periods of time, determined by
accreditation and federal regulations.

-Collection
-review
-storage
-retentions

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31
Q

QSEs

  1. Information Management

what important groups is under here

A

laboratory information systems LIS incorporates all the processes necessary to manage incoming and outgoing patient information using unique identifies (patient and samples) and limits who can access the confidential information which is protected by law

  • Confidentiality
  • Requisitions
  • Logs and records
  • Reports
  • LIS

-against loss of data
-testing info
-sharing documents not using email
-secure and monitored access
-planning for information needs
-integrity of data transfers or transmission
-information availability during downtown
-analysis, design, and documentation of lab processes
-verification and validation of lab processes
-quality control of lab process
-managing and controlling changes in lab processes

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32
Q

QSEs
Performance block

Nonconformance management
10. Occurrence management

A

-An error or event that should not have happened

-complains
-mistakes and problems
-root cause analysis
-immediate actions
-corrective actions
-preventative actions

example of dealing: recognize, report, initiating, documenting

call in safety issues

,management notification of reports

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33
Q

QSEs

  1. Assemnents
A

Laboratory assessment = a tool for examining laboratory performance and comparing it to standards or benchmarks of the performance of other laboratories.

May be internal or external

ISO (Internal Standards Organization) – requires accredited laboratory auditors to compare results from similar laboratories to assess laboratory
performance.

Audits may be internal or external

mainly accreditation inspections related

proficiency testing for test accuracy

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34
Q

QSEs

Continual improvement
12. Process improvement

A

-The deming cycle
-PDCA cycle : Plan, Do, Check, Act
-prioritization
-impact vs effort assements
-protective and corrective actions
-problem resolutions

Lab 1st identifies issues then gathers the info…a
plan is made for improvement…plan
implemented…data gathered and assessed…plan is
updated..corrective action is taken to ensure plan
effective ..then process begins cycle again

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35
Q

who are labs audited by

A

ISO (Internal Standards Organization)

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36
Q

who conducts the accreditations inspections

A

the college of physicians and surgeons CPSS

you get a certificate of accreditation
every 305 CPSS and every 2 years ASHI

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37
Q

T/F QSES does not gurantee and error free lab

A

T

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38
Q

T/F ISO and CLSI are compatible

A

T

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39
Q

ISO 9001:2015

A

Quality Management System- Requirements

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40
Q

ISO/IEC 17025:2017

A

General requirements for the competence of testing and calibration laboratories

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41
Q

ISO 15189:2012

A

Quality management in the clinical laboratory

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42
Q

QMS01

A

A Quality Management System Model for Laboratory
Services

This guideline provides a model for medical laboratories to
organize the implementation and maintenance of an effective
quality management system

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43
Q

Quality

A

in Learning Step 1 was defined as “degree of excellence”. It can now be
expanded and clarified to “providing consistent services which meet or exceed
the needs of the customers (patients)’’

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44
Q

A benchmark

A

serves as the standard of excellence or performance level against which a
process, in this case laboratory service, is measured. If the service does not
meet a certain benchmark, then the quality must be improved

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45
Q

Continuous Quality Improvement Program (CQI)

A

is the activity associated with improving
the laboratory’s ability to constantly improve the quality of the lab processes.

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46
Q

Quality Management Systems (QMS)

A

) can be defined as the “achievement of quality as a
continuous process involving all personnel at all levels of an organization in
the pursuit of excellence in every process, with the ultimate objective being
quality patient care”. To facilitate QMS, all employees must be empowered
and tools to assist in measuring variation in lab results (preventative &
corrective) tools to evaluate statistics and to continuously find ways to improve
procedures and comply with accreditation expectations.

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47
Q

Empowerment

A

means providing staff with opportunities, the authority and resources to settle
quality issues in which they are directly involved.

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48
Q

Accreditation

A

is a non-governmental, external, peer review process for assessment of
healthcare facilities, laboratories or educational programs against a certain
benchmark. It provides a professional judgement about the quality of the
facility and encourages continued improvement. It also provides a good
indication to the public that each accredited facility is capable of functioning at
the required level of competence.

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49
Q

ISO 15189

Accreditation

A

Standards must be met for an organization to be accreditedà
Accreditation Canada (AC) Diagnostics accreditation program
assess the ability of a facility to perform diagnostic testing with
formal recognition of this competence through accreditation to
the ISO 15189 Plus requirements.

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50
Q

Laboratory Quality Assurance Program
(LQAP) administrated by whom

A

College of Physicians and Surgeons of
Saskatchewan

  • The Laboratory Quality Assurance Program (LQAP) is responsible for establishing the requirements and standards of medical laboratories in the province of Saskatchewan and to ensure their compliance with the Medical Laboratory Licensing Act and Regulations
  • The LQAP consists of two types of committees comprised of medical and technical experts in the relevant discipline
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51
Q

Internal Quality Assurance Procedures

A
  • Internal quality assurance à focused around testing of patient clinical samples
  • Monitoring is by the facility or department so then internal
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52
Q

review pre -post analytical images that have many ex

A
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53
Q

External Quality Assurance Programs

A
  • EQA is used to evaluate laboratory testing accuracy
  • EQA tools are shipped from the provider directly to the laboratories
    on a rotational basis. Testing is performed in the same manner as
    a patient specimen.
  • LQAP mandates that EQA assessments be performed for all tests
  • EQA providers for Saskatchewan are:
    * The College of American Pathologists (CAP)
    * One World Accuracy
    * Clinical Microbiology Proficiency Testing (CMPT)
    • American Proficiency Institute (API)
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54
Q

Quality Assurance Audit

A
  • Provides the lab with knowledge of how well it follows its own quality control program
  • By conducting its own internal quality audit assures that the lab is providing reliable results. It assesses the validity of the results.
  • It is achieved by reviewing daily QC data in the lab as well as cumulative reports over a time frame
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55
Q

Continuous quality
improvement

A
  • PDSA cycle
  • Continually asking questions
    every step of every process in
    the laboratory to see if there
    are ways to improve eg) speed
    up processes/improve
  • Huddle/meeting discussions,
    safety alert system reviews,
    audit reviews, staff suggestions
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56
Q

CLSI vs ISO

A

Non-profit organization that brings together the varied perspectives and expertise of the worldwide laboratory community for the advancement of a
common cause
-developed the quality management system
model used in training for QMS and is fully compatible with ISO

vs
* An international standard dedicated to Quality Management Systems (QMS)

-established standards for industrial manufacturing

57
Q

problem solving process the MC in test

IOS MED

A

1 Input: A phlebotomist complains that inpatients are never properly identified.
2 Occurrence Indicator: The phlebotomist finds an inpatient without a wristband.
3 Standard: All inpatients must have wristbands when they are admitted to hospital. No procedure will be performed on a patient unless they have a
wristband.
4 Monitor : Effective immediately, the number of patients without wristbands will be
counted for the next 30 days by the phlebotomy team.
5 Evaluate : The lab supervisor will evaluate the data and give her recommendations to the nursing supervisor.
6 Document: The lab supervisor will document the entire process including the results
from monitoring, recommendations for further action, and the results of
any corrective action that was taken.

58
Q

Occurrence or Non-Conforming Event
Evaluation should include:

A

problem description, action plan, monitoring, summary of results and recommendations, correct the problem.

59
Q

RRID

A

Recognizing
* Recognize when a reportable even occurs
* Reporting
* Report the even to appropriate person
* Initiating
* Initiate corrective action
* Documenting
* All events and their corrective action must be documented

60
Q

LO2 begins
Pre-Analytical Variables

what minimizes them

A
  • Factors that can affect patient’s test results before the specimen is tested in the lab.
  • QA minimizes this risk before testing
61
Q

Policy Manuals

A
  • Outline administrative and operational issues
  • Ensures effective communication
  • Everything must be documented
  • Ensures a standard of quality in the work
  • Policy manuals are a useful tool for how the lab should be
    organized and complete
62
Q

Laboratory Logs
LIS

A
  • Internal manuals or computerized records of patient specimens arriving at a specific department
  • LIS = Laboratory Information Systems
63
Q

Procedure manuals

A

SOPs (standard operating procedures) step by step
instructions on how to perform something

64
Q

TAT or Turn around time

A
  • = time sample collected to when result released
  • This is also monitored/data assessed and helps identify problems, corrections and can affect patient treatment
65
Q

What are the two most important steps
before collecting a patient specimen?

A
  1. Patient Identification
  2. Patient Preparation
66
Q

Calibrators are

A

solutions with an exact known concentration of analytes

  • Used to adjust systems to
    an established reference
    method
  • How? The instrument
    measures the calibrator and
    adjusts the signal to match the
    given values. Plotting the signal
    on the Y-axis versus analyte
    conc. on the X-axis creates a
    calibration curve. The purpose
    of a calibration curve is to
    establish the relationship
    between the conc. of analyte
    and the magnitude of the signal
    given by the measuring device.
    (linear or non-linear)
67
Q

Standards

A

can be considered calibrators, but they are usually a pure chemical whereas
calibrators usually have several exact known analytes in a similar matrix to what is being tested
(ie. Serum or plasma).

68
Q

Controls

A

are substances which contain one or more known analytes which are used to verify the
accuracy and precision of measurements. They can be biological or synthetic in nature.

  • A patient-like material ideally made from human serum, urine or spinal
    fluid.
  • Should be tested in the same manner as patient samples
  • Known ranges
  • Usually contains many different analytes in one bottle
  • Good laboratory practice requires testing normal and abnormal controls
    for each test at least daily to monitor the analytical process
  • QC statistics are recorded on LJ charts, and Westgard Rules are
    considered
69
Q

Precision

A

refers to the reproducibility of a result or how often the same result is generated by
repetitive testing.
* Can indicate random errors but it does not indicate that an instrument is
reporting the correct result, which is accuracy

For example, a technologist may be required to pipet 2 mL of deionized water
into 30 test tubes. If the technologist’s skill is precise, all 30 tubes will contain exactly 2 mL of
water.

70
Q

Accuracy

Who are the only one who has it

A

infers the correctness or closeness with which the measurement comes to the true
value.

Only calibrators/standards have accurate or true values. For example, a solution may be
known to contain 2.5 to 2.9 mmol/L of a substance. If the substance is analyzed, a determined
value of 2.6 mmol/L would be considered accurate, while a value of 4.0 mmol/L would not be
accurate.

71
Q

Reliability refers to a

A

degree of accuracy and precision over an extended period of time under variable conditions.

-Accuracy & precision reflect how well the test method performs day to day in the lab. The other two, sensitivity and specificity, deal with how well the test is able to distinguish disease from absence of disease.

For example, the VW Beetle which drove well with few problems over
several years of ownership, demonstrating accurate and precise driving capabilities, was
considered to be a “reliable” car.

72
Q

Specificity

A

infers the ability to accurately measure one component without interference by other
components.
* Specificity is the ability of a test to correctly exclude patients who do not have a given disease.
The more specific the test is, the less false-positive results

For example, if one were interested in eating only the red candies in a box of
Smarties, one would not want to pick any other colour, such as purple, green, blue, etc. When
evaluating a method in the clinical lab we use negative controls to assess specificity.

73
Q

Negative controls

A

are samples which are lacking in the component we are interested in detecting.

If the method is specific and a negative control is tested, our test result should be
negative.

74
Q

Sensitivity

A

infers the ability to measure small amounts of a component.

  • Sensitivity is the ability of a test to correctly identify patients who have a given disease or
    condition. The more sensitive a test, the less false-negative results will be produced
  • If a test is 90% sensitive then 10% of people tested could be false-negative or found normal.
75
Q

Positive controls

A

contain a small concentration of the component we are interested in detecting. If the method is sensitive and a positive control is tested, our test result should be positive.

76
Q

Error

A

is inexactness in measurement; for example, estimating the money in your wallet as $100
when it truly is $85.04. In the lab we are concerned with analytical errors, which are errors that
occur during the analysis of a sample. Analytical errors are divided into systematic and random.

77
Q

Analytic period: Systematic errors

This is a change in what

A

are associated with a change in accuracy. Systematic errors affect all theresults of a method in either a positive or negative fashion. Such errors will be of the same magnitude and in the same direction and are generally predictable, identifiable and correctable.

For example a technologist might introduce a systematic error into a spectrophotometric method
by erroneously setting zero absorbance using the first standard instead of distilled water. This
will cause all consequent absorbance readings to be off by the amount of absorbance of the first
standard

78
Q

common causes of systematic errors

A
  • stray light
  • scratches on cuvettes
  • improper sample storage
  • inaccurate standard graphs
  • outdated reagents
  • instruments which have an incorrect zero Absorbance
79
Q

Random errors

Change in what

A

are associated with a change in precision. Random errors are more difficult to
monitor in the lab because they happen without prediction or regularity. Random errors can be
due to carelessness and inattention

80
Q

Common causes of random error in the clinical laboratory are:

A
  • transcription errors
  • inaccurate patient identification
  • inaccurate patient or sample preparation
  • dirty glassware
    variation
81
Q

Variation

A

is change or deviation in results that can have a significant effect on the precision and
accuracy of lab results. The lab attempts to control variation by evaluating methods through
statistical means.

82
Q

Variations in sample analysis that labs must regularly deal with include:

A
  • physiological variations such as age, sex and diet
  • differences in technique of specimen collection
  • differences in technique by those performing the test method
83
Q

Qualitative variables

A

are observable characteristics such as urine colour and clarity.

84
Q

Quantitative variables

A

refer to numerical observations such as length of time of a method, the
concentration of an analyte in a sample or the size of an object

85
Q

Variables are classified into two types: discrete and continuous
1) Discrete variables

A

are those observations which can be counted.

For example, the number of
pennies saved in a day or the number of test tubes a lab uses in a month.

86
Q

2) Continuous variables

A

are those for which any value within a particular range is possible.

For example, a 19 year old individual is somewhere between 19 years, 1 day old and 20 years. A 5
mL volumetric pipette may measure somewhere between 4.99 and 5.03 mL.

87
Q

A population is a

A

large body of data which does not have to be finite. It is impossible to
measure each member of a population; therefore we evaluate a sample to make inferences about
the population. The sample is any part of the population and should be a random representative
of the population. In this way, every member of the population has an equal opportunity of
being chosen

88
Q

T/F When we receive a new lot # QC it is analyzed for several days (usually along side the current lot#) to determine the control range (>20 samples/20 days of each Low, Normal, or High controls)

A

T

89
Q

Measurement of Variability affected by

A

-operator technique
-environmental conditions
-performance characteristics of the measurement

90
Q

3 Measures of Central Tendency

A

Mode, median, mean

91
Q

mode

A

the value which occurs with the
greatest frequency

92
Q

median

A

the value at the center or
midpoint of the observations

93
Q

mean

A

the calculated average of the
values
-The mean is the lab’s best estimate of the analyte’s true value for a specific level of
control

94
Q

Normal Distribution

A
  • When data have a normal spread or distribution, the
    median, mean and mode are similar or identical values
  • All values symmetrically distributed around the mean
  • Characteristic “bell-shaped” curve
  • Assumed for all quality control statistics

To determine level of
precision the lab is performing
at…the dispersion of the data
about the mean is considered

95
Q

Standard Deviation (S) or SD

Principle measurement of

A
  • SD is the principle measure of variability used in the laboratory
  • It is a statistic that quantifies how close numerical values (QC values) are in relation to
    each other.
  • Precision is often used interchangeably with standard deviation
  • Used to monitor on-going day-to-day performance
  • = the standard (or typical) amount that scores deviate from
    the mean
96
Q

Consistent SD

A

low standard deviation, low imprecision

97
Q

Inconsistent SD

A

high standard deviation, high imprecision

98
Q

CV formula

A

SD/ mean x 100= x.x%

the lower the better

99
Q

ACCEPTABLE CV for Manual methods is

A

less than or equal to 10%

100
Q

ACCEPTABLE CV for Instrument methods

A

3.0% or less

101
Q

CV

The better the x the x cv

A
  • The better the precision the lower the CV
  • CV is the great statistical equalizer
  • Measure of relative variability
102
Q

4 Frequency Distribution Curves

A
  • Data table
  • Frequency table
  • Bar graph*
  • Histogram*
103
Q

Gaussian or Normal Distribution

A

It is the key to the statistical quality control
* The mean, median and mode are identical
* Used to verify the on-going performance of analytical systems

+ 1 SD 68% of the time
+ 2 SD 95% of the time
+ 3 SD 99.7% of the time

104
Q

How can we relate Gaussian to
Standard Deviation and Probability?

A
  • We can predict that the data will fall within a specific
    percentages of the mean on the Gaussian curve
  • 95% of the results/data points will fall within + 2SD
105
Q

T/F random errors = SD increase= shit in precision

A

T

106
Q

T/F systemic errors lead to mean change = shift in accuracy

A

T

107
Q

What is a reference range?

A

= range of results for clinically 95% of healthy people
* If they fall outside this reference range this indicates a possible disorder/clinical issue
* It is the range that a patient’s results should typically fall within if they are healthy

108
Q

Control range

A

= the acceptable range of a known control sample for an analyte in
order to monitor the precision and accuracy of our analytical system

109
Q
  • A reference range is dependent on the population being tested
  • And also dependent on the individual being tested
  • What does this mean?
A

There are physiological variables, laboratory variables, and/or patient indicators

110
Q

For most lab tests we do not just give out
reference intervals unless they are in a
patient result chart why?

A

Variance between laboratories

111
Q

When to re-evaluate
Reference ranges?

A
  • Method is modified,
    removed or added
  • Method becomes
    automated
  • Population changes
    significantly
  • Method changes entirely
112
Q

Calibrators/Standards

A
  • Multiple calibrators/diluted standards in increasing
    concentrations are measured and results are
    plotted on a graph/curve which is used to
    extrapolate or calculate the concentration of
    analytes in QC and patients
  • Automated analyzers store the calibration data
  • Frequency of calibrations depends on the analyzer
    and the methodology (set by manufacturer)
113
Q

Common Reasons why calibration fails?

A
  • Improper mixing of calibrator
  • Improper constitution of calibrator
  • Improper mixing in instrument
  • Instrument sample delivery issue
  • Change in calibrator lot #
  • Contaminated reagent/calibrator
  • Expired reagent/calibrator
  • Impure water system
114
Q

When to Calibrate

A
  • New lot # reagent loaded on analyzer
  • When required as per manufacturer (intervals)
  • When troubleshooting (QC is out)
  • After maintenance procedures
  • QC is ALWAYS run after calibration
115
Q

Quality Control Testing
* The ISO calls this process, ‘Ensuring the Quality of
Examinations

A

This is achieved by employing error detection
mechanisms to safeguard the examination or
analytical phase

116
Q

Criteria for Control material

A
  1. Patient-like material (human serum, urine, or spinal fluid)
  2. Have a known quantity of analyte present to cover spectrum
    of possible results test menu (low, normal, high)
  3. Must be stable for extended time
  4. Material should be reproducible
    * Vial to vial homogenous
    * Reconstitution must be the same
  5. Easy to use
  6. Contain all constituents you need to measure
    * Ex. Every test you will run on a patient must be present in the control samples
117
Q

Commercial Controls

A
  • Purchased as kits or boxes with several vials of lypophilized material
  • Each box has a lot#
  • A specific amount of diluent added to each vial to reconstitute
  • Material resembles human material
  • All pre-tested for presence of Hepatitis and HIV
118
Q

Blind Duplicate Patient samples as controls

A
  • A patient sample may serve as a control
  • Usually qualitative analysis
119
Q

liquid stable vs lyophilized IQCs

A

ready to use vs need additions bcs they are free dries

120
Q

advantages vs disadvantages of commercial controls

Assayed vs nonassayed

A

assayed prior by manufacturer and unassayed not tested prior

assayed: expensive, used to evaluated accuracy and precisions , avoids lab erroes

unassayed: cheaper, precision only, avoids manufacturer errors

121
Q

in house controls

A

uses pooled sera

122
Q

covid electronic controls vs internal control

A

if the electronic control was working vs if the sample was enough

123
Q

how many variables for control

A

at least 20-30

124
Q

outlier

A

outside 3SD

125
Q

Every QC system or lab should have at least 2 (preferably 3)
levels of controls that are run daily (low, normal, high)
* Why?

A

sick patients will have these diff levels

126
Q

QC range is established now you have to monitor QC in the lab
* QC chart used is called

A

Levey-Jennings or LJ chart

20-30 day period 1-3Sd and mean
1 control leverl on 1 chart

127
Q

What happens if some
data points fall outside
the Gaussian pattern
(3SD)?
The Gaussian curve
would widen…indicates what error

A

widen=random error

128
Q

What if 68% of
values are shifting to
one side?
Gaussian curve has
shifted to one side of
mean and indicates

A

shifted= systemic errors

129
Q

T/F LJ is basically a Gaussian on its side separated by time as a frequency

A

T

130
Q

LJ chart 3 must have rules in labs

A

1, every lab has a graph systme
2, daily control values are plotted vs time
3, lines are drawn to conncet

131
Q

T/F * Precision and long-term accuracy are confirmed on a LJ chart
by control values that remain clustered about the mean with
little variation in the upward or downward direction

A

T

132
Q

What to do after the results are plotted on LJ?

A
  • The technologist needs to assess the quality of the run
  • The technologist should look for systematic error and
    random error
  • Long term inaccuracy is identified on LJ by either a trend
    or a shift
  • Trends and shifts are systematic errors
133
Q

Systematic Error

A

A change in the mean of the control values
* Change in the mean may be gradual and demonstrated as a trend in control values
* Or it may be abrupt and demonstrated as a shift in control values

134
Q

review shift vs trend causes image

A
135
Q

There is unacceptable (unexpected)random error that is any
data point outside the expected population of data

A

outside 3sd

136
Q

shift

A

control on one side of the mean 6 consecutive days

137
Q

trend

A

control moving in one direction heading toward an out of control value

138
Q

Advantages of LJ

A
  • Good visual representation of precision and accuracy
  • Easy to interpret
139
Q

Disadvantages of LJ

A
  • Time to maintain data
  • Must be plotted at the time of assay and in order
  • Acceptable conditions must be met or prevent release of patient results
  • Westgard rules provide some practical solutions to the disadvantages
    of LJ
140
Q

There are usually more than one test/analyte tested in each
bottle of QC… what if you run all the tests that are on your
analyzer on level 1 and level 2 QC….and all the tests are “in
control” and acceptable except the glucose????

A

report only if the test is not gluose related

this indicates there is something with the reagnet, the QC bottles are fine

QC (2 decks)

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