Exam 5: Quality Assurance in Hematology and Hemostasis Testing

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?

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?

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

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)?

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

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

The precision limits of a method are defined by

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

Proper specimen collection and patient satisfaction are components of

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

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?

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

Which of the following is true regarding reference ranges?

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

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

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?

The best way to prevent errors in the laboratory is to

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

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?