MLT 118 Exam 5

Which of the following is not part of measure central tendency :

A. Median

B. Mode

C. Range

D. Mean

Range

The value that occurs within the greatest frequency is the…

Mode

The value at the center or midpoint of the observations is the….

Median

The calculated average of the values (add all value and divide by total number of values)

Mean

Most clinical chemistry tests are…

quantitative

The following are measures of central tendency?

Mode

Mean

All listed

Median

All listed

Obtaining the same result after testing the same specimen three times is called test:

Precision

The ability to obtain the published result on a control specimen is referred to as:

Accuracy

A procedure with a coefficient of variation of 10% is considered:

Imprecise

The results of a precision study cholesterol are shown below.

What is the coefficient of variation for the study?

Mean = 150 mg/dL

Standard deviation = 15 mg/dL

10.0%

What is the Coefficient of Variation for a set of numbers when:

1 SD = 6.8, mean = 80, and the (range for ± 1 SD = 73.2 - 86.8)?

8.5%

The 99% confidence limit refers to values that fall within:

Range equal to the mean plus or minus two standard deviations

Range equal to the mean plus or minus one standard deviation

Range equal to the mean plus or minus four standard deviations

Range equal to the mean plus or minus three standard deviations.

Range equal to the mean plus or minus three standard deviations.

In a normal distribution of results, the mean value +/- 2 SDs will include what percentage of the population?

95.5%

99.7%

68.2%

100.0%

95.5%

A cross-reacting compound in a serum sample may result in which of the following?

A) A reliable result

B) A precise result

C) An accurate result

D) A discordant result

B) A precise result

What does the equation TP/(TP + FN)  measure?

Sensitivity

Specificity

Positive Predictive Value

Negative Predictive Value

Sensitivity

Testing of unknown specimens from an outside agency that provides validation of the quality patient results is:

Internal Quality Control

External Quality Control

Electronic Quality Control

Proficiency Testing

Proficiency Testing

If the QC result for the normal level of control is outside the range defined for that control level, normal patient results may be reported. True or False?

False

What are the 95% confidence limits for a control mean of 140mg/dL and a standard deviation (s) of 2.5mg/dL?

138 - 142

132.5 - 147.5

137.5 - 142.5

135 - 145

135-145

Exp. 95% confidence limits is ± 2S so take the mean (140) and ± it by 2 to get the low and high ranges.

Proportional error in a method is characterized by which of the following?

The magnitude of the error increases as the concentration of analyte increases.

The magnitude of the error stays the same over a wide concentration range.

The magnitude of the error decreases as the concentration of analyte increases.

The magnitude of the error is inversely proportional to concentration.

The magnitude of the error increases as the concentration of analyte increases.

A deterioration of Quality control while in use can result in which of the following types of errors?

Transcriptional

Clerical

Systematic

Random

Systematic

The result of a precision study of glucose are shown below. What is the coefficient of variation for this study?

Mean= 100mg/dL   Standard Deviation= 5mg/dL

7.5%

10%

2.5%

5%

5%

A 1_3s quality control rule violation is defined as:

One control result that exceeds ±4 s.

One control result that exceeds ±3 s.

Three consecutive controls results that exceed ±3 s.

One control result that exceeds ±1.3s.

One control result that exceeds ±3 s.

± 1 SD is what percentage?

68.3% (of the time)

± 2 SD is what percentage?

95.5% (of the time)

± 3 SD is what percentage?

99.7% (of the time)

If a test is said to have sensitivity of 95%, statistically, this means that it will:

Detect 5 out of 100 true positives

Miss 5 out of 100 true negatives

Detect 5 out of 100 true negatives

Miss 5 out of 100 true positives

Miss 5 out of 100 true positives

Which type of error is represented in the image below?

Systematic

Occurs without prediction or regularity

Random errors

Operator technique or pipetting mistakes are considered…

random errors

Error that is consistently low or high, constant as well.

Systematic Errors

Deterioration of reagents in use and Deterioration of control material while in use are considered…

systematic errors

Which of the following best describe random error?

Results may be either above or below the mean.

Results are consistently below the mean.

Results are consistently above the mean.

Results must eb either above or below the mean, but must be the same percentage away from the mean.

Results may be either above or below the mean.

Clinical laboratory personnel have the least control over which of the following conditions?

A. Pre-examination variables

B. Examination variables

C. Post-examination variables

D. All of the above

A. Pre-examination variables

What is a lyophilized control?

A control that does not resemble human blood.

A control that is dehydrated to powder.

A control that is outside of the expected range.

A control that is made directly by the laboratory.

A control that is dehydrated to powder.

The preparation of a Levey-Jennings quality control chart for any constituent of serum requires:

A minimum of 20-30 analyses of control serum over a period of 20-30 days.

20-30 analyses of control serum on one day, one batch.

Daily analyses for 1 month with the use of aliquots from more than one lot control serum.

20-30 analyses performed by one person.

A minimum of 20-30 analyses of control serum over a period of 20-30 days.

A Levy-Jennings chart is considered post-analytical phase of Quality assurance cycle.

A) True

B) False

False, it’s analytical.

A 1(3s) quality control rule violation is defined as:

A) One control result that exceeds ±3s

B) One control result that exceeds ±1.3s

C) Three consecutive controls results that exceed ±3s

D) One control result that exceeds ±4s

A) One control result that exceeds ±3s