GMAT Critical Reasoning
Before lead poisoning starts to cause serious damage, it can be detected through a screening test. Every test sometimes produces false positives, indicating that the people tested have lead poisoning, when, in fact, they do not; a false negative indicates that people do not have lead poisoning when, in fact, they do. To detect lead poisoning most accurately, medical workers should use the screening test which has the lowest proportion of false negative results.
Which of the following, if true, most strongly supports the above recommendation?
- A The test with the lowest false negative rate also requires the most time-intensive laboratory procedures.
- B All screening tests used to detect lead poisoning have the same proportion of false positive results.
- C The proportion of inconclusive test results is equal for all screening tests used to detect lead poisoning.
- D The screening test which has the lowest proportion of false negative results causes side effects less frequently than other tests.
- E The treatment for lead poisoning, called chelation therapy, sometimes has serious side effects.
Correct Answer: B