PRELIM LEC: Quality Assurance (BISHOP)

Question 1

The foundation for monitoring performance (known
as QC) is

Answer 1

descriptive statistics

Question 2

This symmetrical
shape is often called a

Answer 2

“bell curve.”

Question 2

describes many continuous laboratory variables and shares several unique characteristics

Answer 2

Gaussian distribution

Question 3

summarizes the above relationships between the area under a Gaussian distribution and the SD

Answer 3

“68–95–99 Rule”

Question 4

provides objective an objective measure of the line of best fit for the data

Answer 4

linear regression analysis

Question 5

Three factors are generated in a linear regression

Answer 5

the slope, the y-intercept, and the
correlation coefficient (r)

Question 6

An alternate approach to visualizing paired data is the difference plot, which is also known as the

Answer 6

Bland-Altman plot

Question 7

The difference between test and reference method results is called

Answer 7

error

Question 8

is a measure of the strength of the
relationship between the two methods

Answer 8

correlation coefficient (r)

Question 9

There are two kinds of error measured in COM experiments:

Answer 9

random and systematic

Question 10

is present in all measurements and can be either
positive or negative, typically a combination of both positive and negative errors on both sides of the assigned target value

Answer 10

Random error

Question 11

influences observations consistently in one direction (higher or lower).

Answer 11

Systematic error

Question 12

Systematic error can be further broken down into

Answer 12

constant error and proportional error

Question 13

exists when there is a continual difference between the test method and the comparative method
values, regardless of the concentration

Answer 13

Constant systematic error

Question 14

exists when the differences between the test
method and the comparative method values are proportional to the analyte concentration

Answer 14

Proportional error

Question 15

are used to draw conclusions (inferences)
regarding the means or SDs of two sets of data

Answer 15

Inferential statistics

Question 16

is the cause of lack of precision or the imprecision in a test

Answer 16

Random analytic error

Question 17

Ability of a method to detect small quantities or
small changes in concentration of an analyte

Answer 17

Analytic sensitivity

Question 17

Ability of a method to detect only the analyte it is
designed to determine, also known as cross-reactivity

Answer 17

Analytic specificity

Question 18

Range of analyte that a method can quantitatively report, allowing for dilution, concentration, or other pretreatment used to extend AMR

Answer 18

CRR (clinically reportable range)

Question 18

Also known as linear or dynamic range. Range of analyte concentrations that can be directly measured without dilution, concentration, or other pretreatment

Answer 18

AMR (analytic measurement range)

Question 19

Lowest amount of analyte accurately detected by a method

Answer 19

LoD (limit of detection)

Question 20

Lowest amount of analyte that can be reported while achieving a precision target (e.g., lowest concentration at which a CV of 10% may be achieved)

Answer 20

LoQ (limit of quantitation)

Question 21

Refers to the difference between the measured value and the mean expressed as a number of SDs. An SDI = 0 indicates the value is accurate or in 100% agreement; an SDI = 3 is 3 SDs away from the target (mean) and indicates inaccuracy. SDI may be positive or negative

Answer 21

SDI (standard deviation index)

Question 22

Dispersion of repeated measurements about the mean due to analytic error

Answer 22

Precision

Question 23

How close the measured value is to the true value due to systematic error, which can be either constant or proportional

Answer 23

Accuracy

Question 24

Error always in one direction (may be constant or proportional).

Answer 24

Systematic error

Question 25

Difference between the true value and the measured value

Answer 25

Bias

Question 26

Type of systematic error where the magnitude
changes as a percent of the analyte present, error dependent on analyte concentration.

Answer 26

Proportional error

Question 26

Type of systematic error in the sample direction and
magnitude; the magnitude of change is constant and not dependent on the amount of analyte

Answer 26

Constant error

Question 27

Ability of a test to detect a given disease or condition

Answer 27

Diagnostic sensitivity

Question 27

Error varies from sample to sample. Causes include
instrument instability, temperature variations, reagent variation, handling techniques, and operator variables.

Answer 27

Random error

Question 28

Random error plus systematic error

Answer 28

Total error

Question 29

Standard deviation index. ((Test method value) − (Reference method value))/(Reference method SD), analogous to Z-score.

Answer 29

SDI

Question 30

Chance of an individual having a given
disease or condition if the test is abnormal

Answer 30

Positive predictive value

Question 30

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

Answer 30

Diagnostic specificity

Question 31

Chance an individual does not have a given
disease or condition if the test is within the reference interval

Answer 31

Negative predictive value