Method Evaluation and Quality Control

A Gaussian distribution is usually a. Bell shaped b. Rectangular c. Uniform d. Skewed

The following chloride (mmol/L) results were obtained using a new analyzer: What is the mean? a. 108 b. 105 c. 109 d. 107

. The following chloride (mmol/L) results were obtained using a new analyzer: What is the median? a. 108.5 b. 105 c. 112 d. 107

For a data value set that is Gaussian distributed, what is the likelihood (%) that a data point will be within ±1 SD from the mean? a. 68% b. 99% c. 95% d. 100%

The correlation coefficient a. Indicates the strength of relationship in a linear regression b. Determines the regression type used to derive the slope and y-intercept c. Is always expressed as “b” d. Expresses method imprecision

If two methods agree perfectly in a method comparison study, the slope equals and the y-intercept equals. a. 1.0, 0.0 b. 0.0, 1.0 c. 1.0, 1.0 d. 0.0, 0.0 e. 0.5, 0.5

Systematic error can best be described as consisting of a. Constant and proportional error b. Constant error c. Proportional error d. Random error e. Syntax error

Examples of typical reference interval data distribution plots include all of the following except a. ROC b. Nonparametric c. Parametric d. Bimodal

A reference range can be verified by a. Testing as few as 20 normal donor specimens b. Literature and vendor material review c. Using samples from previously tested hospital patients d. Using pharmacy-provided Plasmanate spiked with target analyte concentrations

Reference interval transference studies a. Are used to verify a reference interval b. Are used to establish a reference interval c. Require as many as 120 normal donors d. Use a 68% reference limit for acceptability

Diagnostic specificity is the a. Ability of a test to correctly identify the absence of a given disease or condition b. Chance an individual does not have a given disease or condition if the test is within the reference interval c. Chance of an individual having a given disease or condition if the test is abnormal d. Ability of a test to detect a given disease or condition

To evaluate a moderately complex laboratory test, all of the following must be done except: a. Analytical sensitivity and specificity b. Verification of the reference interval c. Accuracy and precision d. Reportable range

An ROC includes all of the following except: a. Perfect test = an area under the curve <1.0 b. Equals receiver operator characteristic c. Plots sensitivity and 1 – specificity d. Can be used to compare two different tests

For method development studies, which analytical performance test should be done first? a. Imprecision studies b. Comparison of methods (COM) c. Recovery d. Interference studies e. Does not matter, they all need to be done

For the following series of laboratory values, the vendor has indicated that a true value is 6.0. Series = 5, 4, 5, 6, 7, 5, 3, 8, 5, 9, 5, 4, 5, 6. The SDI (standard deviation index) is: a. –0.3 b. +0.3 c. +1.0 d. –0.7

Comparison of method studies: a. Estimate systematic error. b. Use primary QC material and standards that span the reportable range. c. Are usually completed within 4 working days. d. Are not required for nonwaived tests

Interference studies typically use as an interferent. a. All of these b. Hemolyzed red cells c. Highly icteric samples d. Highly lipemic samples

• Allowable analytical error is a. A combination of random and systematic error b. Best if it is greater than the total error c. Used only for research and initial evaluation studies