RODRI CC2 Flashcards

1
Q

system of ensuring accuracy and precision in the laboratory buy including quality control reagents in every series of measurements

A

Quality control

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2
Q

it is a process of ensuring that analytical results are correct by testing known samples that resemble patient samples

A

Quality control

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3
Q

process of monitoring the charactersitics of analytical processes, detects analytical errors, prevent reporting of inaccurate patient test results

A

Quality control

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4
Q

one component of the quality assurance system, and a part of performance monitoring that occurs after a test has been established

A

Quality control

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5
Q

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

A

Sensitivity

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6
Q

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

A

Specificity

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7
Q

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

A

Accuracy

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8
Q

accuracy is estimated using 3 types of studies:

A

Recovery
Interference
Sample comparison

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9
Q

determines how much of the analyte can be identified in the sample

A

Recovery study

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10
Q

determines id specific compounds affect the laboratory tests like hemolysis, turbidity, icteric

A

Interference

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11
Q

used to assess presence of error [inaccuracy] in actual patient sample

A

Accuracy

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12
Q

ability of an analytical method to give repeated results on the same sample that agree with one another

A

Sample comparison

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13
Q

ability of an analytical method to give repeated results on the same sample that agree with one another

A

Precision or reproducibility

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14
Q

degree by which method is easily repeated

A

practicability

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15
Q

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

A

Reliability

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16
Q

ability of the analytical method to detect the proportion of individuals w/ the disease

A

diagnostic sensitivity

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17
Q

indicates the abilioty of the test to generate more true-positive results and few false-negative

A

Diagnostic sensitivity

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18
Q

Diagnostic sensitivity formula

A

Sensitivity= 100 x diseased individuals w/ positive test/ total # of individuals W/ TEST

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19
Q

ability of the method to detect true-negatives w/ very few false-positives.

A

diagnostic specificit

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20
Q

Diagnostic specificity formula

A

Sensitivity= 100 x diseased individuals w/ NEGATIVE test/ total # of individuals W/O DISEASE

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21
Q

2 Kinds of Quality Control

A

Intralab QC
Interlab QC

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22
Q

involves analyses of control samples together w/ the px samples

A

Intralab QC

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23
Q

detects changes in performance bet. present operation & stable operation

used to determine state-of-the-art interlaboratory performance

A

Intralab QC

interlab QC

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24
Q

important in the daily monitoring of accuracy and precision of ana. methods

important in maintaining long-term accuracy of the analytical methods

A

Intralab QC

Interlab QC

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25
Q

detects both random and systematic errors in a
[1week cycle/daily basis]

allows ID of analytical errors within [1week cycle/daily basis]

A

Inralab QC

daily basis
1wk cycle

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26
Q

gold standard for clinical laboratory external QC testing

A

College of American Pathologists [CAP] Proficiency Program

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27
Q

Which of the statements are true?
What makes the other statement false?

A series of unknown samples are sent to the laboratory from the reference laboratory or authorized program provider

Unknown samples must be tested by the laboratorians who regularly perform analysis of a patient specimen using the different reagents and equipment for actual patient specimens

A

A series of unknown samples are sent to the laboratory from the reference laboratory or authorized program provider

different = same

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28
Q

Which of the statements are false? What makes them false?

Analysis of the unknown samples should not be completed within the usual time as for the routine samples

Unknown samples should be treated like a reference specimen to determine the true essence of accuracy

A

should be completed

reference= unknown

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29
Q

Results of the proficiency testing [must be/must not be] shared with other laboratories during the testing period. Comparison studies can be made [when? ] to identify areas for improvement

A

must not be shared

after the testing cycle

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30
Q

Some proficiency tests are [quantitative or qualitative] however for chemistry, it should be [quantitative or qualitative]

A

qualitative

quantitative

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31
Q

If there is no available proficiency testing program for a certain analyte, it is required to implement a ______________

A

non-proficiency test scheme

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32
Q

in external WC, difference of greater than ___SD in the results indicates that a laboratory is not agreement w/ the rest of the laboratories included in the program

A

2

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33
Q

TRUE OR FALSE
If in case of clinical laboratory failed to identify or resolve an error or discrepancy in the process, the facility is at risk of continuous operation and may be recommended for closure.

A

True

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34
Q

The ultimate goal of ______ is to ensure our clinicians that patients results are accurate.

A

Proficiency testing

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35
Q

Modified T/F

Proficiency testing allows each laboratory to compare and evaluate test results or outcomes with those laboratories that use the same methods

Data obtained from the proficiency testing can be used to continuously improve test performance, and also serve as a troubleshooting guide when investigating error.

A

Both are true

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36
Q

What are the three objectives of a Quality control?

A
  1. To check the stability of the machine
  2. To check the quality of reagents
  3. To check technical [operator] errors
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37
Q

The accuracy of any assay depends on the ______ how they are originally constituted and how they remain stable overtime

A

Control solutions

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38
Q

General chemistry assays used [2/3], levels of control solutions, while immunoassays used [2/3] levels

A

[2] and [3]

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39
Q

To establish statistical quality control on a new instrument or new lot number of control materials, the different levels of control material must be analyzed for ___ days.

A

20 days

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40
Q

For highly precised assays (with less than [1%/10%] such as blood gases, analysis for ____ days is adequate

A

1%

5 days

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41
Q

Thee are expected values represented by intervals of acceptable values with upper and lower limits

A

Control limits

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42
Q

Modified T/F

If the expected values are within the desired control limits. The clinicians are assured that the test results are accurate and precise

Control limits are calculated form the mean and variance

A

True

Variance = standard deviation

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43
Q

The ideal control limit is between _____

A

+/-2SD

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44
Q

Modified T/F

Use of a double lot for an extended period allows reliable interpretative criteria to be established which will permit efficient identification of and assay problem

When charging to a new lot number, laboratorians use the newly calculated [SD/mean] value as the target [SD/mean] but retain the [SD/mean] value, but when more data are obtained, all values should be
averaged to get the best estimates of the mean and SD.

A

Double = single

Mean - Mean - SD

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45
Q

Modified T/F

Determination of the mean and SD for the assayed controls is also advisable because this process
improves the performance characteristics of statistical control procedures.

A

Asseyed = unassayed

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46
Q

Characteristics of an Ideal QC Material:

A
  1. Resembles human sample.
  2. Inexpensive and stable for long periods .
  3. No communicable diseases.
  4. No matrix effects/known matrix effects.
  5. With known analyte concentrations (assayed control).
  6. Convenient packaging for easy dispensing and storage.
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47
Q

Quality control materials should resemble human sample and be available for a [minimum/maximum] of one year (same lot number) - different lot numbers of the [same/different] material have different concentrations
which requires new estimates of the mean and standard deviation.

A

Minimum

Same

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48
Q

Human control materials are preferred but because of limited sources and biohazard considerations,
______ control materials are used.

A

Bovine

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49
Q

Bovine-based QC material [is/is not] the choice for immunochemistry, dye-binding and certain bilirubin
assays.

A

Is not

50
Q

Modified T/F

QC materials should be the same matrix as the specimens being tested, for example, measurement
of glucose in serum should have control solutions that are prepared from serum.

Matrix effects are results of improper product manufacturing, use of unpurified human and
nonhuman analyte additives and altered protein components.

A

Both are true

51
Q

Modified T/F

Control materials can be purchased with and without assayed values.

Assayed controls are more expensive but can be used as internal checks for accuracy.

A

and = or

internal = external

52
Q

Modified T/F

Reconstitution of lyophilized control materials must be properly done to avoid incorrect control
values.

Stabilized frozen controls do not require reconstitution but may have different characterizations
same to actual patient specimens.

A

True

Same = compare

53
Q

The test method must be compared always with a method of acceptable accuracy such as the
__________ (gold standard).

A

standard reference method

54
Q

Modified T/F

It is recommended by Westgard et al and Clinical Laboratory Improvement Amendments (CLIA)
that 40 to 100 samples be run by each method in duplicate on the same day over 8 to 30 days
ideally within 4 hours, to determine its accuracy and precision.

If only 40 samples will be measured, daily analysis in duplicate of 2 to 5 specimens should be
followed for at least 7 days.

A

30 days = 20 days

7 days = 8 days

55
Q

_________ analyses of each sample by each method (test method and reference method) are
recommended, with the duplicate samples analyzed in different runs and in different order of
analysis on the two runs (should be performed within 4 hours).

A

Duplicate

56
Q

The rationale for performing repeated assays is to _________ that affect precision.

A

detect random errors

57
Q

After analyses, samples with wide difference should be ______ to rule out technical errors as
the source of ______.

A

Repeated

Variation

58
Q

The most important characteristic of method evaluation is to determine if the total error (random and systematic error) is [more/less] than the allowable error (Ea).

A

Less

59
Q

Are errors encountered in the collection,preparation and measurementof samples,
including transcription and releasing of laboratory results.

A

Variations

60
Q

Basis for varying differences between repeated measurements

A. Systematic error
B. Random error
C. Clerical error
D. Constant error

A

B. Random error

61
Q

It is present in al measurements: it is due to chance.

A. Systematic error
B. Constant error
C. Clerical error
D. Random error

A

D. Random error

62
Q

Type of error which varies from sample to sample

A

Random error

63
Q

It is due to instrument, operator and environmental conditions (variations in techniques) such as
pipetting error, mislabeling of samples, temperature fluctuation, and improper mixing of sample
and reagent.

A

Random error

64
Q

Modified T/F

Systematic Error is an error that influences observations consistently in two direction (constant difference).

Systematic Error is detected as neither positive nor negative bias - often related to calibration problems,
deterioration of reagents and control materials, improperly made standard solutions,
contaminated solutions, unstable and inadequate reagent blanks, leaky ion selective electrode
(¡SE), failing instrumentation and poorly written procedures.

A

Two = one

Neither nor = Either or

65
Q

It is a measure of the agreement between the measured quantity and the true value.

A. Systematic error
B. Constant error
C. Clerical error
D. Random error

A

A. Systematic error

66
Q

Modified T/F

Constant error refers to a difference between the target value and the assayed value while percent error results in greater deviation from the target value due to higher sample concentration.

Percent error exists when there is a continual difference between the comparative method and the
test method regardless or the concentration while constant error it exists when the difference between the test method and the comparative method
values is proportional to the analyte concentration.

A

True

Percent error = constant error
Constant error = Percent error

67
Q

Modified T/F

Systematic error is the highest frequency of clerical errors occurs with the use of handwritten labels and
request forms.

Proportional error is independent of sample concentration.

A

Systematic error = clerical error

Proportional error = constant error

68
Q

Enumerate the indicators of analytic performance:

A
  1. Internal QC
  2. Proficiency testing
  3. Accreditation
  4. Quality
  5. Assurance monitoring and laboratory utilization
69
Q

The first step in method evaluation

A

The precision study which estimates the random error.

70
Q

Modified T/F

To study imprecision or random error, 2 control solutions are run [once/twice] a day in a 10- to 20-day
period - by testing multiple samples on different days, a better assessment of random error over time is achieved.

The total imprecision analysis is the most accurate measure of performance that would affect
the laboratory values a clinician might observe and reflects differences such as in the work of
technologists, pipetting and temperature fluctuations of the analyzers.

A

Twice

True

71
Q

Determine if it’s pre, ana, or post error

  1. Incorrect anticoagulant to blood ratio (short draw)
  2. Equipment/instrument malfunction
  3. Incomplete centrifugation
  4. Incorrect sample and reagent volume
  5. Long turnaround time
  6. Mishandled specimen
A
  1. Pre
  2. Ana
  3. Pre
  4. Pre
  5. Post
  6. Pre
72
Q

Refers to all the activities that take place before testing, such as test ordering and
sample collection.

A

Preanalysis

73
Q

Modified T/F

The most frequent analytical errors include improperly filling the sample tube, placing
specimens in the wrong containers or preservatives, and selecting the incorrect test.

The post analysis stage consists of the laboratory activities that actually produce a result, such as
running a sample on an automated analyzer. Postanalysis comprises patient reporting and result
Interpretation.

A

Analytical = Pre

Post analysis = analysis

74
Q

Modified T/F

The length of time elapsed between drawing and the separation of serum or plasma from the
cells can be a factor in analytical testing.

Laboratory personnel were responsible for 29% of the errors with regard to laboratory
results.

A

True

Laboratory = Non laboratory

75
Q

Modified T/F

Online computer input is the most error-free means of requesting laboratory tests.

Most laboratory errors occur in the preanalytic and postanalytic stages.

A

Both are true

76
Q

What study is this?

Error rates were reported to range from 0.05% to 0.61%, and the distribution of
errors among the testing stages was similar, with most (32%-75%) occurring in the preanalytic
stage and far fewer (13%-32%) in the analytic stage

A

(Bonini et al, 2002 cited in McPherson and
Pincus 2017).

77
Q

Modified T/F

Allowable error is determined for each test method and is expressed either in measurement units of the
analyte (mmol/L) or percentages.

Allowable error is based on the quality of error that will negatively affect clinical decisions.

A

True

Quality = quantity

78
Q

Modified T/F

The total error (random, proportional, constant and systematic error) must be less than the Ea or
fixed limits for a method to be considered acceptable.

If the total error is greater than Ea, corrections must be made to reduce the error or the method
be rejected.

A

Both are true

79
Q

STATISTICS

______ a measure of central tendency.
______ measure of the dispersion of values from the mean.
______ is called the standard deviation squared
______ percentile expression of the mean; an index of precision

A

Mean
Standard Dev
Variance
Coefficient of variation

80
Q

The difference between T-test and F-test

A

F-test is used to determine whether there is a statistically significant difference between the
standard deviations of two groups of data while T-test is the difference between the means of two groups of data

81
Q

Terminologies:

_____ midpoint of a distribution
_____ used to compare the means or standard deviations of two groups of data
_____ the simplest expression of spread or distribution;
_____ the difference between the value of a data point and the mean
value divided by the group’s SD

A

Median
Inferential statistics
Range
SD Index

82
Q

Modified T/F

Statistical analyses are used to determine the types and quantity of error that a method has, and
to decide whether the test is still valid or acceptable to make clinical decisions.

Parametric tests: t-test and analysis of variance (ANOVA)

A

Acceptable = unacceptable

True

83
Q

3 measures of spread or distribution

A

CV, SD and range

84
Q

______ describes the distribution of all values around the mean.
______ and ______ represent the average distance from the center of the data (mean) and every value
in the data set.
______ allows a laboratorian to compare SDs with different units.

A

SD
SD and variance
CV

85
Q

Modified T/F

The CV of anälyzers described as having reproducible test results can be lower than 1%.

Degree of freedom (n-1) indicates the number of quantities free to vary.

A

Both are true

86
Q

Modified T/F

ANOVA is used to analyze precision data to give estimates of the within-in run, between-run and
total imprecision.

> Method evaluation and statistical analysis are essential, but not sufficient to decide if a test is valid.

A

Both are true

87
Q

The acceptable range is __% confidence limit which is equivalent to ‡

A

95%

88
Q

Modified T/F

QUALITY CONTROL CHART is used to observe values of control materials over time to determine reliability of the
analytical method.

QUALITY CONTROL CHART is utilized to observe and detect analytic errors such as accuracy and imprecision.

A

True

Accuracy = inaccuracy

89
Q

Determine if its [A. Gaussian Curve B. Cumulative sum graph C. Youden/Twin plot D. Shewhart Levey]

  1. It is obtained by plotting the values from multiple analyses of a sample.
  2. It is a graphic representation of the acceptable limits of variation in the results of an analytical
    method.
  3. The points falling from a center but on the 45° line suggest a proportional error, and points
    falling fror the center but not on the 45° line suggest a constant error.
  4. It is very sensitive to small, persistent errors that commonly occur in the modern, low
    calibration-frequencyanalyzer.
  5. it focuses on the distribution of errors from the analytical method rather than the values from a
    healthy or patient population.
  6. It calculates the difference between QC results and the target means.
  7. It is the most widely used QC chart in the clinical laboratory.
  8. it displays the results of the analyses by plotting the mean values for one specimen on the
    ordinate (y-axis) and the other specimen on the abscissa (x-axis).
A
  1. A 7. D
  2. D. 8. C
  3. C
  4. B
  5. A
  6. B
90
Q

Determine if its [A. Gaussian Curve B. Cumulative sum graph C. Youden/Twin plot D. Shewhart Levey]

  1. This plot will give the earliest indication of systematic errors (trend) and can be used with the 13s
    rule.
  2. It occurs when the data set can be accurately described by the SD and the mean.
  3. It easily identifies random and systematic errors.
  4. It is used to compare results obtained on a high and low control serum from different
    laboratories.
  5. It is a population probability distribution that is symmetric about the mean.
    It occurs when data elements are centered around the mean with most elements close to the
    mean.
  6. It allows the laboratorians to apply multiple rules without the aid of a computer.
  7. Common method: V-mask.
    It identifies consistent bias problems; it requires computer implementation.
  8. The total area under the curve is 1.0 or 100%.
A
  1. B
  2. A
  3. D
  4. C
  5. A
  6. D
  7. B
  8. A
91
Q

Determine if its [A. Trend B. Shift C. Outliers]

  1. Shift in the reference range is due to transient instrument differences.
  2. Main cause: Deterioration of reagents
  3. It is formed by control values that either increase or decrease for six consecutive days.
  4. These are caused by random or systematic errors.
  5. It is formed by control values that distribute themselves on one side or either side of the mean
    for six consecutive days.
  6. These are control values that are far from the main set of values.
  7. Main cause; Improper calibration of the instrument
  8. These are highly deviating values.
A
  1. B
  2. A
  3. A
  4. C
  5. B
  6. C
  7. B
  8. C
92
Q

Westgard Control Chart

It recognizes that the use of ______ upper and lower control limits is not enough to identify
analytical problems.

In Westgard, error detection rates can _____ without increasing the false rejection rate.

Westgard used the term _______ to indicate if the analytical process is out of control.

A

Simple
Increase
Control rule

93
Q

It is observed when one control result exceeds the mean +- 3SD; due to random error.

A

1[3s]

94
Q

The last four (or any four) consecutive control results exceed either mean + - 1SD• due to systematic error.

A

4[1s]

95
Q

It is used as a rejection or warning rule when one control result exceeds the mean + - 2SD: for screening purpose

A

1[2]s

96
Q

It is observed when the last 2 control results or 2 results from the same run exceed either the mean + - 2D: due to svstematic error

A

2[2s]

97
Q

The range or difference between the highest and lowest control result within an analytical run exceeds 4s; it is due to systematc error.

A

R[4s]

98
Q

We need to reject an analytical run when
8 consecutive control measurements fall on one side of the mean

A

8x

99
Q

We need to reject an analvtical run when 6 consecutive control measurements fall on one side of the mean

A

6x

100
Q

We need to reject an anavtical run when
seven control measurements “trend” in the same direction, i.e., get progressively higher or progressively lower

A

7[T]

101
Q

reject when 12 consecutive control
measurements fall on one side of the mean

A

12x

102
Q

It is observed when 10 consecutive results are on The Same
side of the mean: due to systematic error.

A

10x

103
Q

We need to reject an analytical run when 2 out of 3 control measurements exceed the mean plus 2s or mean minus 2s control limit

A

2of3[2s]

104
Q

We need to reject an analvucal run when
9 consecutive control measurements fall on one side of the mean.

A

9x

105
Q

We need to reject an analytical run when 3 consecutive control measurements exceed the same mean plus 1s or mean minus 1s control limit.

A

3[1s]

106
Q

It is the concentration range over which the measured concentration is equal to the actual concentration without modification of the method.

A

Linear Range/Dynamic Range

107
Q

It is a set of control and patient specimens assayed, evaluated and reported together.

A

Analytical run

108
Q

It includes effective test request forms, clear instruction for patient preparation and specimen handling, appropriate turn around time for specimen processing, testing and result reporting,
appropriate reference ranges and intelligent result reports.

A

Quality Patient Care

109
Q

It is the probability that a negative test indicates absence of disease. It is the proportion of persons with a negative test who are truly without disease.

A

Negative predictive value

110
Q

It is the probability that a positive test indicates disease; it is the proportion of persons with a positive test who truly have the disease.

A

Positive predictive value

111
Q

Physiologic Limit

Is sometimes referred to as ______.

It helps ______ sample contamination or dilution, inadequate sample volume, inadequate reagent volumes, sudden major problems with the method, or incorrect recording or transmission of the result.

A

absurd value
Detect

112
Q

These are used to measure systematic errors or inaccuracy caused by substances other than the
analyte.

Interferences: hemoglobin, lipids, bilirubin, anticoagulants and preservatives

A

Interference experiments

113
Q

It is a type of analytical testing performed outside the confines of the central laboratory, usually by nonlaboratorian personnel (nurses, respiratory therapists, etc).

Most commonly used POCT: use of portable whole blood glucose meters for the management of patients with diabetes mellitus.

A

Point Of Care Testing (POCT)/Decentralized Testing

114
Q

It can be envisioned as a tripod with program development, assessment and monitoring, and quality improvement forming the three legs.

Is a systematic action necessary to provide adequate confidence that laboratory services will satisfy the given medical needs for patient care.

A

Quality Assurance (QA)

115
Q

Primary Goal of QA

A

To deliver quality services and products to customers.

116
Q

It shows whether a method measures all the analytes or only part of it.

It estimates inaccuracy or systematic error.

A

Recovery experiment

117
Q

Delta check
It is the [less/most] commonly used patient based QC technique.

It requires computerization of test data so that [current/past] results can be compared with past results.

It is the difference between two consecutive measurements of the [same/different] analytes on the same
individual.

A

Most
Current
Same

118
Q

Modified T/F

Predictive value depends on sensitivity, specificity, and prevalence of the disease being test.

Predictive value is when a test cutoff changes, its accuracy (sensitivity/specficity) and predictive value also change.

A

Both are true

119
Q

Bayes’ theorem (predictive value theory) describes the relationship between posttest and pretest probability of disease or no disease based on the sensitivity and specificity of the test.

A

Predictive value

120
Q

Modified true or false

Reference Limit/Reference Interval/Reference Value

It is a value obtained by observation or measurement of a particular type of quantity on a reference individual.

It is a pair of medical decision points that extend the limits of test results for a certain healthy population.

A

Both are true

121
Q

Modified T/F

Reference Limit/Reference Interval/Reference Value

It is the range of values into which 90% of nondiseased individuals will fall - this definition implies that 10% of nondiseased individuals can have laboratory results outside the reference
range.

It is the usual values for a healthy population that represents 90% central tendency.

A

90% = 95%
10% = 5%

90% = 95%

122
Q

Modified T/F

Reference Limit/Reference Interval/Reference Value

It is usually established by the manufacturers of reagents or group of experts

It is mostly determined using nonparametric statistics (CLS| recommended method).

A

Both are true