ABFM Assessment and Evaluation 3 — Questions and Answers
Question 1: A physician wants to evaluate a new screening test for colorectal cancer. Among 1,000 patients, 100 have cancer; the test is positive in 90 of these and negative in 10. Among the 900 without cancer, 180 test positive. What is the specificity of this test?
- 80% (Correct answer)
- 33%
- 50%
- 90%
Correct answer: 80%
Specificity = true negatives / (true negatives + false positives) = 720 / (720 + 180) = 80%.
Question 2: Which USPSTF grade indicates that a preventive service has high certainty of substantial net benefit and should be offered?
- Grade A (Correct answer)
- Grade B
- Grade C
- Grade D
Correct answer: Grade A
USPSTF Grade A recommendations indicate high certainty of substantial net benefit and should be routinely offered to eligible patients.
Question 3: A 55-year-old man with a 30 pack-year smoking history asks about lung cancer screening. Which test and criteria meet USPSTF recommendations?
- Chest X-ray annually starting at age 50
- Low-dose CT scan for ages 50–80 with ≥20 pack-year history who currently smoke or quit within 15 years (Correct answer)
- Sputum cytology every 3 years
- PET scan annually for high-risk smokers
Correct answer: Low-dose CT scan for ages 50–80 with ≥20 pack-year history who currently smoke or quit within 15 years
USPSTF recommends annual low-dose CT for adults aged 50–80 with ≥20 pack-year history who currently smoke or quit within the past 15 years.
Question 4: When assessing a patient's functional status in geriatric evaluation, which instrument specifically measures basic activities of daily living (ADLs)?
- Lawton-Brody IADL Scale
- Barthel Index (Correct answer)
- Timed Up and Go (TUG)
- Short Physical Performance Battery (SPPB)
Correct answer: Barthel Index
The Barthel Index assesses basic ADLs including feeding, bathing, dressing, and mobility.
Question 5: A 62-year-old woman with osteoporosis has a FRAX 10-year major fracture probability of 22% and hip fracture probability of 4%. According to NOF guidelines, what is the appropriate next step?
- Lifestyle counseling only; reassess in 2 years
- Initiate pharmacological treatment (Correct answer)
- Repeat DEXA in 1 year to reassess
- Order bone biopsy to confirm trabecular loss
Correct answer: Initiate pharmacological treatment
NOF guidelines recommend pharmacotherapy when 10-year major osteoporotic fracture probability ≥20% or hip fracture probability ≥3%.
Question 6: In evaluating a chest pain patient in primary care, which feature of the history most strongly suggests a musculoskeletal etiology rather than cardiac ischemia?
- Radiation to the left arm
- Reproducibility with chest wall palpation (Correct answer)
- Association with exertion
- Relief with sublingual nitroglycerin
Correct answer: Reproducibility with chest wall palpation
Chest pain that is reproducible with palpation of the chest wall strongly favors a musculoskeletal cause over cardiac ischemia.
Question 7: A physician is evaluating the performance of a new rapid strep test. Its sensitivity is 86% and specificity is 96%. In a low-prevalence setting (5% strep prevalence), what does a NEGATIVE result most reliably indicate?
- The patient almost certainly has strep throat
- Strep throat is very unlikely (high negative predictive value) (Correct answer)
- The test result is not useful at low prevalence
- Antibiotics should still be prescribed empirically
Correct answer: Strep throat is very unlikely (high negative predictive value)
At low disease prevalence, a negative test with high sensitivity yields a very high negative predictive value, making disease unlikely.
ABFM Assessment and Evaluation 3
A physician wants to evaluate a new screening test for colorectal cancer.
Among 1,000 patients, 100 have cancer; the test is positive in 90 of these and negative in 10.
Among the 900 without cancer, 180 test positive.
What is the specificity of this test?