The control values for both controls for the prothrombin test ...

[809779]

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. Shift
  b. Trend
  c. Random error
  d. Predictable error

Question 2

A test that is positive in all patients who have the disease but also in some who do not have the disease is:
 
  a. Sensitive
  b. Specific
  c. Precise
  d. Reliable

[Koolkid240]

Answer to Question 1

ANS: A
If all results are consistently different from the previous in the same direction, then it indicates a shift in the methodology has occurred. A trend would show a gradual change over time. This is neither a predictable error nor a random error because it is consistent.

Answer to Question 2

ANS: A

Sensitivity (diagnostic) is defined by the number of people with the disease who test positive. In this case, all patients with the disease have a positive result, so the test is very sensitive. The test, however, is not specific because it is also positive in some people who do not have the disease. Reliability refers to the performance stability of a test over time. Precision evaluates reproducibility of the result if repeated multiple times on a specimen.