USMLE Rx 2016 Quiz - Gradiuz

USMLE Rx 2016 Quiz

Quiz generated from USMLE Rx 2016

Want to study this quiz?

Copy it to your free Gradiuz library and make it your own.

Make your own from a PDF
Question 1

Researchers organize subjects into smokers and nonsmokers and then follow them to see who develops COPD. What type of study is this?

  • Cohort study
  • Case-control study
  • Cross-sectional study
  • Phase II clinical trial
Question 2

A study determines the prevalence of COPD in the United States in 2010. What type of study is this?

  • Cross-sectional study
  • Cohort study
  • Case-control study
  • Phase IV clinical trial
Question 3

In a case-control study of smoking and lung cancer, how are subjects divided?

  • Cases are patients with lung cancer and controls are patients without lung cancer
  • Cases are smokers and controls are nonsmokers
  • Cases are patients given the new drug and controls are patients given placebo
  • Cases are monozygotic twins and controls are dizygotic twins
Question 4

Which set correctly lists the outcome measures of cross-sectional, case-control, and cohort studies, respectively?

  • Prevalence, odds ratio, relative risk
  • Relative risk, prevalence, odds ratio
  • Odds ratio, relative risk, prevalence
  • Prevalence, relative risk, odds ratio
Question 5

A phase I clinical trial is conducted in a small number of healthy volunteers to establish safety, toxicity, and pharmacokinetics.

  • True
  • False
Question 6

Which phase of a clinical trial is best suited to detect rare or long-term adverse effects of a drug?

  • Phase IV (postmarketing surveillance)
  • Phase I
  • Phase II
  • Phase III
Question 7

In a triple-blinded clinical trial, who is blinded to each subject's group assignment?

  • The patient, the doctor, and the researchers analyzing the data
  • Only the patient and the doctor
  • Only the researchers analyzing the data
  • The patient, the doctor, and the pharmacist who manufactures the drug
Question 8

A patient asks about her probability of having cervical cancer after a positive Pap smear. What is this measurement called?

  • Positive predictive value
  • Negative predictive value
  • Sensitivity
  • Specificity
Question 9

If a test has a negative predictive value of 100%, its sensitivity must also be 100%.

  • True
  • False
Question 10

How is the false-positive rate calculated from a test's specificity?

  • 1 − specificity
  • 1 − sensitivity
  • 1 / specificity
  • specificity − 1
Question 11

A screening test with high sensitivity is most useful for which purpose?

  • Ruling out disease when the result is negative
  • Confirming disease when the result is positive
  • Measuring the prevalence of disease in a population
  • Determining the relative risk of an exposure
Question 12

A test with 100% specificity will never produce a false-positive result.

  • True
  • False
Question 13

Which formula correctly defines positive predictive value (PPV)?

  • TP/(TP + FP)
  • TP/(TP + FN)
  • TN/(TN + FN)
  • TN/(TN + FP)
Question 14

A diabetes test yields 40 true-positive and 10 false-positive results. What is the positive predictive value?

  • 80%
  • 20%
  • 25%
  • 40%
Question 15

The positive predictive value of a screening test is independent of the prevalence of the disease in the population being tested.

  • True
  • False
Question 16

As the prevalence of a disease increases in a tested population, what happens to the negative predictive value (NPV) of the test?

  • It decreases
  • It increases
  • It stays exactly the same
  • It becomes 100%
Question 17

A diabetes test yields 30 true-negative and 10 false-negative results. What is the negative predictive value?

  • 75%
  • 25%
  • 30%
  • 90%
Question 18

A test with 100% sensitivity has a false-negative rate of 0.

  • True
  • False
Question 19

A hepatitis B virus test has a sensitivity of 85%. What is its false-negative rate?

Fill in the blank

Question 20

An HIV test has a specificity of 75%. What percentage of patients will test false positive?

  • 25%
  • 75%
  • 15%
  • 50%
Question 21

In HIV testing, which assay is highly sensitive and therefore has a high false-positive rate and a low threshold?

  • ELISA
  • Western blot
  • Both have equally high false-positive rates
  • Neither; both have low false-positive rates
Question 22

In HIV testing, which assay is highly specific and therefore has a low false-positive rate and a high threshold?

  • Western blot
  • ELISA
  • Both have equally low false-positive rates
  • Neither; both have high false-positive rates
Question 23

What term describes the probability that a person who has a disease will test positive for it?

  • Sensitivity
  • Specificity
  • Positive predictive value
  • Negative predictive value

Made with Gradiuz

Turn any PDF into quizzes, flashcards and summaries - free.

Try it yourself