Question 1

The antinuclear antibody (ANA)test is positive in almost all people who have systemic lupus erythematosus (SLE).It is also positive in some patients who do not have SLE.The antideoxyribonucleic acid (anti-DNA)test is positive only in people with SLE but not in all who do.Which of the following is true?

Accepted Answer

A)  The ANA test is a good screening test, and anti-DNA test is a good confirmatory test.
B)  The anti-DNA test is a good screening test, and the ANA test is a good confirmatory test.
C)  Both are good screening tests for SLE.
D)  Neither of these tests is valid. A

Question 2

One of two controls that have been evaluated over the last 28 days gives a result on day 29 between 2 and 3 SDs of the mean;the other control is within 2 SDs of its mean.What is the correct procedure to follow?

Accepted Answer

A)  Ignore the result unless it happens again the next day.
B)  Rerun the control and, if acceptable, continue with patients.
C)  Recalibrate the instrument.
D)  Open new vials of controls and repeat both controls. B

Question 3

A laboratory comparing its results to those of other laboratories on the same specimen is an example of

Accepted Answer

A)  precision monitoring.
B)  internal quality control.
C)  external quality control.
D)  delta checks. C

Question 4

A patient's white blood cells (WBCs)are counted on an automated cell counter 10 times.The mean white count is 8000/mL,and the standard deviation (SD)is 300.What is the coefficient of variation (CV)?

Accepted Answer

A)  0.04%
B)  2.6%
C)  3.8%
D)  26%

Question 5

Which of the following would most likely be associated with the situation described in Question 11?

Accepted Answer

A)  operator error
B)  fading light source
C)  miscalibrated instrument
D)  starting a new lot number of thromboplastin reagent

Question 6

Which of the following groups of patients should not be included in establishing moving averages using red cell indices?

Accepted Answer

A)  chemotherapy patients
B)  female patients
C)  obstetric patients
D)  surgical patients

Question 7

The precision limits of a method are defined by

Accepted Answer

A)  the mean.
B)  the SD.
C)  sensitivity.
D)  specificity.

Question 8

A patient specimen is analyzed on an instrument known to be in control from previous assays performed on a calibrated instrument and gives a hemoglobin result of 13.2 g/dL.Two hours later it is evaluated on another instrument that is being evaluated for purchase by the laboratory.The result is 11.8 g/dL.This result,when compared with the first,is

Accepted Answer

A)  acceptable agreement.
B)  reportable.
C)  precise agreement.
D)  inaccurate.

Question 9

Proper specimen collection and patient satisfaction are components of

Accepted Answer

A)  quality control.
B)  quality assurance.
C)  reliability.
D)  precision.

Question 10

A clinical laboratory scientist performs 30 replicate hemoglobin determinations on a single blood sample.When statistics are used to determine the precision of the method,the mean is 13.8 g/dL and 1 SD is 0.1 g/dL.This means that 95.5% of the results on this specimen lie

Accepted Answer

A)  between 13.4 and 14.2 g/dL.
B)  between 13.6 and 14.0 g/dL.
C)  between 13.5 and 14.1 g/dL.
D)  between 13.7 and 13.9 g/dL.

Question 11

The tubing that brings the lyse reagent to the hemoglobin cuvette on an automated cell counter is pinched and not delivering any reagent.All hemoglobin values are greater than 20 g/dL.This represents what type of error?

Accepted Answer

A)  random
B)  imprecision
C)  constant systematic
D)  proportional systematic

Question 12

A purchased hemoglobin standard is used to adjust a hemoglobinometer.This standard is being used as a

Accepted Answer

A)  control
B)  precision check
C)  delta check
D)  calibrator

Question 13

Which of the following is true regarding reference ranges?

Accepted Answer

A)  should be derived from reference books
B)  need to be determined only for adults
C)  can be established by running the test procedure on 10 healthy people
D)  are ranges of values for an analyte in normal healthy people

Question 14

The control values for both controls for the prothrombin test were ranging between the mean and ±1 SD for the first 19 days of use.Starting on day 20,the values for both were consistently between +1 and +2 SDs.This is an example of a

Accepted Answer

A)  shift.
B)  trend.
C)  random error.
D)  predictable error.

Question 15

A test that is positive in all patients who have the disease but also in some who do not have the disease is

Accepted Answer

A)  sensitive.
B)  specific.
C)  precise.
D)  reliable.

Question 16

A laboratory gets numerous complaints regarding the length of time it takes hematology results to get to the emergency department.What would be an appropriate response?

Accepted Answer

A)  Make this a quality assurance project.
B)  Ignore the complaints.
C)  Explain why it takes so long.
D)  Tell the employees to work faster.

Question 17

The best way to prevent errors in the laboratory is to

Accepted Answer

A)  purchase high-quality instruments from reputable vendors.
B)  hire only well-trained, conscientious workers.
C)  have quality management.
D)  perform external quality control procedures.

Question 18

What does the CV calculated in Question 2 describe about the white cell counts?

Accepted Answer

A)  accuracy
B)  reliability
C)  proper calibration
D)  precision

Question 19

The following hemoglobin results,reported in g/dL,are obtained on a hospitalized patient on 3 consecutive days:
$\frac{\text { Day 1 }}{14.3} \quad \frac{\text { Day } 2}{11.5} \quad \frac{\text { Day } 3}{144}$
The SD for this hemoglobin method was calculated in Question 18.A delta check was obtained on day 2.Controls were run as appropriate each day and were all within limits for this procedure.
What is the most probable reason for the day 2 result when compared with those for days 1 and 3?

Accepted Answer

A)  It is within the 95.5% confidence levels for this test.
B)  It may represent an error in patient identification.
C)  The patient had a major blood loss between days 1 and 2.
D)  It is within the 99% confidence levels for this test.

Exam 5: Quality Assurance in Hematology and Hemostasis Testing