05 QA and Hemostasis Testing

#18 and #19

**CALCULATIONS. Look both up on the Quiz Bank

Reference ranges

- Ranges of values for an analyte in normal healthy people - _______ should be determined by evaluating a group of perhaps as many as 120 normal healthy people for the same analyte. If the analyte differs in different groups, based on data such as age and sex, then it must be determined for each group if at all possible.

External QC

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

Make this a quality assurance project.

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?

Re-run QC

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?

Quality assurance

Proper specimen collection and patient satisfaction are components of:

CV

The ______ is a measure of precision or how well a result can be reproduced. It allows comparisons of assays with different means and is a unitless number, although usually expressed as a percentage.

Screening; Confirmatory

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 anti-deoxyribonucleic acid (DNA) test is positive only in people with SLE but not in all who do. The ANA test is a good _________ test and the Anti-DNA test is a good ________ test

Hiring only well-trained, conscientious workers

The best way to prevent errors in the laboratory is to ensure:

3.8% ***% CV = (SD/mean) x 100

The mean white count is 8000/mL, and the standard deviation (SD) is 300. What is the coefficient of variation (CV)?

SD

The precision limits of a method are defined by:

Constant systematic

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? (Clue: Answer is not "Proportional systematic" because this would mean the values will be increased RELATIVE to the original result (That is, not consistently above 20 g/DL)

Calibrator

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

Sensitive

A test that is positive in all patients who have the disease but also in some who do not have the disease is: (Clue: targetting POS for patients with disease as opposed to NEG for healthy patients)

Shift

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: (Clue: Consistently different from the previous results IN THE SAME DIRECTION)

Starting a new lot # of reagent

Which of the following would most likely be associated with a SHIFT?

Accuracy

____________ is how close a result is to the true value; proper calibration is required to obtain accuracy.

Reliability

______________ is how well a method holds both accuracy and precision over time

Chemotherapy

______________ patients are not ideal for establishing moving everages of red cell indices

Inaccurate

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: _______ (Clue: Answer is not "Not precise" due to lacking multiple re-runs of assay to compare to)