Quality Control Flashcards

1
Q

Is a complete system of creating and following procedures and policies

A

Quality Assurance (QA)

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2
Q

What is the aim of quality assurance?

A

To provide the most reliable patient laboratory result
To minimize errors in the pre-analytical, analytical, and postanalytical phases

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3
Q

A system of ensuring accuracy and precision in the laboratory by using quality control materials in every series of measurement

A

Quality Control (QC)

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4
Q

Testing of patient samples can proceed even without performing QC first. True or false?

A

False; before you run patient samples, you have to run quality control testing first

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5
Q

Overall process used to ensure that laboratory results meet the requirements for healthcare services to patients

A

Quality Management (QM)

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6
Q

Quality Management is otherwise known as

A

TQM (Total Quality Management)

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7
Q

Intervals of acceptable values with upper and lower limits

A

Control limits

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8
Q

Most commercially prepared QC materials are lyophilized. What does lyophilized means?

A

They come in powdered or pulverized form

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9
Q

Ideal control limit

A

± 2SD

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10
Q

Who applied the principles of analyzing QC in the laboratory? When?

A

Levey & Jennings, 1950s

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11
Q

These are specimens analyzed for QC purposes

A

Quality Control Materials/ Control Solutions

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12
Q

Control level with concentrations above or below the normal range of the analyte being tested

A

Level 2 (Abnormal Control)

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13
Q

A sample taken from the total volume of the quality control material

A

Aliquot

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14
Q

Level of control that contains normal levels for the analyte being tested

A

Level 1 (Normal Control)

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15
Q

Level of controls commonly used in immunoassays:

A

Level 1 (Low Control)
Level 2 (Normal Control)
Level 3 (High Control)

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16
Q

What to do if a quality control result shows that one/some values are out of control?

A

Find the error → take corrective measures → repeat quality control testing = if the control results are within the control limits, you can now proceed testing patient samples

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17
Q

What are the objectives of performing Quality Control?

A

To check the stability of the machine/analyzers utilized in the Chemistry Laboratory
To check the quality of the reagents
To check technical (operator) errors

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18
Q

The errors we encounter in the laboratory from the pre-analytical, analytical and post-analytical phases of testing

A

Variation/Variables

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19
Q

In the operation of a QC system, is it allowed to accept errors?

A

Errors are acceptable BUT WITH LIMIT

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20
Q

The standard confidence limit in Clinical Chemistry is set at

A

± 2SD

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21
Q

If the error repeatedly occurred (even if corrective actions are already made). Reject or Accept?

A

Reject

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22
Q

If an error occurred, but it was corrected thru corrective actions. Reject or Accept?

A

Accept

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23
Q

Involves the analyses of control samples and the patient specimen; use for the daily monitoring of accuracy and precision of analytical methods

A

Intralab Quality Control (Internal QC)

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24
Q

How often should we perform QC within a clinical laboratory?

A

Daily

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25
Q

In Intralab Quality Control (Internal QC). Quality Control Materials are: Assayed or Unassayed?

A

Assayed; values are known and given

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26
Q

Involves proficiency testing programs that periodically provide samples of unknown concentrations to participating clinical laboratories

A

Interlab Quality Control (External QC)

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27
Q

In Interlab Quality Control (External QC). Quality Control Materials are: Assayed or Unassayed

A

Unassayed; values are known by the National Reference Laboratories but are NOT given to the participating clinical laboratories

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28
Q

Gold standard for clinical laboratory external QC testing

A

College of American Pathologists (CAP) proficiency program

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29
Q

Transcribe NEQAS

A

National External Quality Assurance Scheme

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30
Q

Importance of proficiency testing programs for laboratories

A

Important in maintaining long-term accuracy of analytical methods
To determine state-of-the-art interlaboratory performance

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31
Q

Reference Laboratory for Microbiology and Parasitology

A

Research Institute for Tropical Medicine (RITM)

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32
Q

Reference Laboratory for Immunology and Serology

A

San Lazaro Hospital / STD AIDS Cooperative Central Laboratory (SLH/SACCL)

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33
Q

Reference Laboratory for Hematology and Coagulation

A

National Kidney and Transplant Institute (NKTI)

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34
Q

Reference Laboratory for Clinical Chemistry

A

Lung Center of the Philippines (LCP)

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35
Q

Reference Laboratory for Drugs of abuse, Toxicology, Micronutrient Assay, Environmental and Occupational Health

A

East Avenue Medical Center (EAMC)

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36
Q

These laboratories are mandated to provide laboratory referral services such as confirmatory testing, surveillance and research

A

Reference Laboratories

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37
Q

Type of laboratory that function to maintain Quality Assurance Programs

A

Reference Laboratories

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38
Q

The 10 analytes measured/quantified under the NEQAS for CC

A
  1. Glucose
  2. BUN (blood urea nitrogen)
  3. Creatinine
  4. Uric Acid
  5. Cholesterol
  6. Triglycerides
  7. Albumin
  8. Sodium
  9. Potassium
  10. Chloride
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39
Q

During NEQAS, what will happen to laboratories that have submitted results outside the confidence limit?

A

Possible closure of laboratory

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40
Q

It is the ability of an analytical method to measure only the analyte of interest

A

Specificity

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41
Q

What are the different parameters of quality control?

A

Sensitivity
Specificity
Accuracy
Precision
Practicability
Reliability

42
Q

It is the nearness or closeness of the assayed value to the true value or target value

A

Accuracy

43
Q

It is the ability if an analytical method to measure the smallest concentration of the analyte of interest

A

Sensitivity

44
Q

A pregnancy hormone that is detected in urine and blood of patients who are pregnant

A

Human chorionic gonadotropin (HCG)

45
Q

These are used to determine how good a given test is at predicting and detecting the presence of a disease

A

Diagnostic sensitivity and Diagnostic specificity

46
Q

It is the closeness of the assayed value to the repeated value

A

Precision

47
Q

It is the degree by which an analytical method is easily repeated

A

Practicability

48
Q

it is the ability of an analytical method to maintain accuracy and precision over an extended period of time during which equipment, reagents and personnel may change

A

Reliability

49
Q

These are used to determine how good a given test is at predicting and detecting the presence of a disease

A

Diagnostic sensitivity and Diagnostic specificity

50
Q

Ability of a test to detect a given disease or condition

A

Diagnostic sensitivity

51
Q

Ability of a test to correctly identify the absence of a given disease or condition

A

Diagnostic specificity

52
Q

Patient has the disease or condition and positive of the test

A

True positive (TP)

53
Q

Patient does not have the disease or condition
and negative of the test

A

True negative (TN)

54
Q

Patient has the disease or condition but is negative of the test

A

False negative (FN)

55
Q

Patient does not have the disease or condition but is positive of the test

A

False positive (FP)

56
Q

Formula for Diagnostic Sensitivity

A

TP/(TP+FN)

57
Q

Formula for Diagnostic Specificity

A

TN/(TN+FP)

58
Q

Error that occur due to chance

A

Random error

59
Q

Factors contributing to random error

A

Instrument
Reagent
Operator
Environmental conditions

(pipetting error, mislabeling in
samples, temperature of analyzer, and improper mixing of sample or reagent)

60
Q

Error that can influence the observations consistently in one direction

A

Systematic error

61
Q

Corrective actions for systematic error

A

Check on equipment/machines
Check reagents
Check quality control materials
Check standard solutions
Review standard operating procedures

62
Q

Factors contributing to systematic error

A

Calibration problems
Deterioration of reagents and control materials
Improperly made standard solutions
Contaminated solutions
Unstable and inadequate reagent blanks
Leaky ion selective electrode
Poorly written procedures

63
Q

An error where the magnitude of change is constant and not dependent on amount and concentration of analyte

A

Constant systemic error

64
Q

Cause of constant error

A

Interference or contamination

65
Q

Error dependent on analyte concentration

A

Proportional error (Slope/Recent error)

66
Q

Cause of proportional error

A

Poor recovery of analyte during an analysis

67
Q

Means that the total error is less that the standard confidence limit, which is ±2 SD, and the performance is acceptable

A

Allowable analytic error (EA)

68
Q

Principle of allowable analytic error

A

If RE and SE (total error) < Ea, then the performance of the test is considered acceptable

69
Q

What to do if the total error is greater than the allowable error?

A

Corrections must be made to reduce the error or the method is rejected

70
Q

Measure of central tendency

A

Mean

71
Q

The most frequently used measure of variation

A

Standard deviation (SD or s)

72
Q

An index of precision

A

Coefficient of variation (CV)

73
Q

Measure of variability

A

Variance (V)

74
Q

Bell-shaped curve/Normal distribution curve/Normal frequency curve

A

Gaussian curve

75
Q

It is the most widely used QC chart in the clinical laboratory

A

Shewhart Levey-Jennings Chart

76
Q

Advantages of Shewhart Levey-Jennings Chart

A

Can apply multiple rules without the aid of the computer
Easily identifies random and systematic errors

77
Q

Formed by the control values that continue either to increase or decrease for a period of six consecutive days by passing the mean

A

Trend

78
Q

Main cause of trend

A

Deterioration of reagents

79
Q

Solution to trend

A

Open new set of reagent/ QC materials

80
Q

Criteria for trend

A

Increase or Decrease for 6 consecutive days (control values)
Control values should pass the mean

81
Q

Formed by the control values that distribute themselves on one side of the mean for a period of six consecutive days

A

Shift

82
Q

Main cause of shift

A

Improper calibration of the instrument

83
Q

Solution to shift

A

Recalibrate instruments

84
Q

Criteria for shift

A

Distribute themselves on one side of the mean
6 consecutive days

85
Q

Are highly deviating values far from the main set of values

A

Outliers

86
Q

Rules that are used to further judge whether control results are out of control or in control

A

Westgard Rules

87
Q

One control observation exceeds the mean +2SD

A

1 2S

88
Q

A warning rule that initiates testing of control data by other rules

A

1 2S

89
Q

One control observation exceeds the mean+3SD

A

1 3S

90
Q

Rule that allows high sensitivity to random error

A

1 3S

91
Q

Two control observations consecutively exceed either the mean ±2SD

A

2 2S

92
Q

Rule that allows high sensitivity to systematic error

A

2 2S

93
Q

Four consecutive control observations exceed either mean ±1SD

A

4 1S

94
Q

Rule that allows the detection of systematic error

A

4 1S

95
Q

The range or difference between the highest and lowest control result within an analytical run exceeds +2SD and -2SD

A

R 4S

96
Q

Rule that allows detection of random error

A

R 4S

97
Q

Ten consecutive control observations are on the same side of the target mean

A

10X

98
Q

The 10X rule allows the detection of random or systematic error?

A

Systematic error

99
Q

Warning rule for screening purposes

A

1 2S

100
Q

Rule/s that detects and with high sensitivity to random error

A

1 3S
R 4S

101
Q

Rule/s that detects and with high sensitivity to systematic error

A

2 2S
4 1S
10X