Question 1

The results of a precision study urea nitrogen are shown below. What is the per cent coefficient of variation for the study?
Mean = 15 mg/dL
Standard deviation = 1.5 mg/dL
Variance = 2.0 mg/dL
A) 1.5%
B) 2.0%
C) 10.0%
D) 15.0%

Accepted Answer

The percent coefficient of variation (%CV) is calculated as the standard deviation divided by the mean, multiplied by 100. So, for this study, %CV = (1.5 / 15) * 100 = 10.0%.

Question 2

A urea nitrogen result is falsely elevated and it was discovered that the previous sample on the sample carousel has abnormally high serum glucose. Which of the following can cause this error?
A) Pipetting an extra volume of diluents into the sample with the falsely elevated glucose
B) Carryover
C) A leak in the reagent-dispensing probe
D) Double pipetting of the sample with the elevated glucose result

Accepted Answer

Carryover from the previous sample with abnormally high serum glucose can contaminate the subsequent sample, leading to a falsely elevated urea nitrogen result. This occurs when residue from one sample is inadvertently transferred to another.

Question 3

The term that describes a procedure in which the CLS compares two consecutive laboratory results on a patient is:
A) Discordant check.
B) Correlation check.
C) Limits check.
D) Delta check.

Accepted Answer

Delta check is the correct term for a procedure in which consecutive laboratory results on a patient are compared to identify significant changes or discrepancies.

Question 4

A deteriorating light source in a spectrophotometer can result in which of the following types of errors?
A) Systematic
B) Systemic
C) Type I
D) Type II

Accepted Answer

A deteriorating light source in a spectrophotometer leads to systematic errors because it consistently affects the measurements in one direction, either by decreasing or increasing the measured values across all samples.

Question 5

Which of the following is a procedure that is used to substantiate the continued accuracy of the test system throughout the laboratory reportable range of the tests result of the test system?
A) Quality control
B) Calibration
C) Bias testing
D) Regression analysis

Accepted Answer

Calibration is the procedure used to ensure that a test system continues to provide accurate results across its reportable range.

Quiz 3: Laboratory Statistics, Method Development and QC

The results of a precision study urea nitrogen are shown below. What is the per cent coefficient of variation for the study? Mean = 15 mg/dL Standard deviation = 1.5 mg/dL Variance = 2.0 mg/dL

A urea nitrogen result is falsely elevated and it was discovered that the previous sample on the sample carousel has abnormally high serum glucose. Which of the following can cause this error?

The term that describes a procedure in which the CLS compares two consecutive laboratory results on a patient is:

A deteriorating light source in a spectrophotometer can result in which of the following types of errors?

Which of the following is a procedure that is used to substantiate the continued accuracy of the test system throughout the laboratory reportable range of the tests result of the test system?