USMLE Step 3 Quiz: Preventive Care And Screening

What this quiz covers

This quiz focuses on Preventive Care And Screening, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 3.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. Order fasting lipid profile for ASCVD risk (correct answer)
2. Order coronary CT angiography screening
3. Order BNP level for heart failure screening
4. Order troponin to assess silent ischemia

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 50-year-old man has cardiovascular risk factors and no recent lipid testing, the recommended step is ordering a fasting lipid profile for ASCVD risk, aligning with ACC-AHA guidelines. Choice A is correct because it matches ACC-AHA recommendations for lipid screening in adults with risk factors to assess 10-year ASCVD risk. Choice B is incorrect because it suggests coronary CT angiography, which is not routinely recommended for primary prevention screening without symptoms. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 2

1. She should receive the recombinant zoster vaccine series. (correct answer)
2. She is not eligible for any zoster vaccine due to her methotrexate use.
3. She should receive the live attenuated zoster vaccine for better immunity.
4. She must temporarily discontinue methotrexate before receiving the vaccine.

Explanation: The Advisory Committee on Immunization Practices (ACIP) recommends the recombinant zoster vaccine (Shingrix) for all immunocompetent adults aged 50 and older, including those on low-dose immunosuppressive therapy such as methotrexate (≤0.4 mg/kg/week). The recombinant vaccine is not a live virus and is safe and effective in this population. The live attenuated vaccine would be contraindicated.

Question 3

1. Screen for type 2 diabetes with HbA1c (correct answer)
2. Screen for type 1 diabetes with autoantibodies
3. No diabetes screening until symptoms develop
4. Screen with random insulin level annually

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 50-year-old obese man with risk factors asks about diabetes screening, the recommended test is screening for type 2 diabetes with HbA1c, aligning with USPSTF guidelines. Choice A is correct because it matches USPSTF recommendations for screening adults aged 35-70 who are overweight or obese. Choice C is incorrect because it suggests no screening until symptoms, ignoring asymptomatic detection benefits. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 4

1. One-time HIV Ag/Ab screening test (correct answer)
2. HIV viral load screening every 6 months
3. CD4 count screening without HIV diagnosis
4. No HIV screening unless symptomatic

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 25-year-old woman with multiple partners has no prior HIV test, the recommended screening is one-time HIV Ag/Ab test, aligning with USPSTF guidelines. Choice A is correct because it matches USPSTF recommendations for screening all adults aged 15-65 at least once. Choice D is incorrect because it suggests no screening unless symptomatic, ignoring routine recommendations. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 5

1. Increase daily physical activity and reduce screen time (correct answer)
2. Start high-protein diet to promote weight loss
3. Begin intermittent fasting without supervision
4. Restrict all dietary fat to zero grams

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 10-year-old boy has BMI at 95th percentile with excessive screen time and soda intake, the prioritized modification is increasing daily physical activity and reducing screen time, aligning with AAP guidelines. Choice A is correct because it matches AAP recommendations for at least 60 minutes of activity daily and limiting screen time to reduce obesity risk. Choice D is incorrect because it suggests restricting all dietary fat, which is not balanced or recommended. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 6

1. DXA scan for osteoporosis screening (correct answer)
2. Whole-body CT for fracture risk
3. Routine serum vitamin D screening only
4. Bone scan annually regardless of risk

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 70-year-old woman has no prior bone density testing, the recommended screening is DXA scan for osteoporosis, aligning with USPSTF guidelines. Choice A is correct because it matches USPSTF recommendations for osteoporosis screening in women aged 65 and older. Choice B is incorrect because it suggests whole-body CT, which is not indicated for fracture risk assessment. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 7

1. One-time hepatitis C antibody screening (correct answer)
2. Monthly hepatitis C RNA screening
3. Routine CMV serology screening
4. No hepatitis C screening until age 50

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 25-year-old woman wants age-based infectious disease screening, the recommended test is one-time hepatitis C antibody screening, aligning with USPSTF guidelines. Choice A is correct because it matches USPSTF recommendations for one-time screening in adults aged 18-79. Choice D is incorrect because it suggests no screening until age 50, ignoring the broad age range. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 8

1. HPV vaccine series initiation (correct answer)
2. Zoster recombinant vaccine
3. Pneumococcal conjugate vaccine (PCV20)
4. RSV vaccine for older adults

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 25-year-old sexually active woman has no prior HPV vaccination, the most important vaccine is HPV vaccine series initiation, aligning with ACIP guidelines. Choice A is correct because it matches ACIP recommendations for HPV vaccination up to age 26 in those not previously vaccinated. Choice B is incorrect because it suggests zoster vaccine, which is recommended starting at age 50. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 9

1. Cervical cytology every 3 years (correct answer)
2. HPV co-testing every 5 years
3. Cervical cytology every year indefinitely
4. No cervical screening until age 30

Explanation: This question tests understanding of preventive care and screening in primary care (USMLE Step 3). Preventive care involves applying evidence-based guidelines to recommend appropriate screenings and lifestyle modifications. In this vignette, the 25-year-old woman has no prior cervical screening, the most appropriate measure is cervical cytology every 3 years, aligning with USPSTF guidelines. Choice A is correct because it matches USPSTF recommendations for cytology every 3 years from ages 21-29. Choice D is incorrect because it suggests no screening until age 30, but screening starts at 21. For teaching, emphasize the importance of staying updated with guidelines, identifying patient-specific risk factors, and prioritizing screenings that provide the greatest benefit. Encourage students to practice applying guidelines in varied scenarios to build confidence in clinical decision-making.

Question 10

1. Begin screening with colonoscopy at age 45, consistent with average-risk guidelines.
2. Schedule a colonoscopy now with random biopsies for dysplasia. (correct answer)
3. Annual screening with a stool-based DNA test is an acceptable alternative.
4. Defer surveillance as long as his disease remains in clinical remission.

Explanation: Patients with inflammatory bowel disease (IBD) are at increased risk for colorectal cancer and require surveillance, not average-risk screening. For patients with left-sided colitis or pancolitis, surveillance colonoscopy should begin 8-10 years after the onset of symptoms. This patient, with a 12-year history, is overdue. The procedure involves taking multiple random biopsies throughout the colon to look for dysplasia.

Question 11

1. Reassure him that screening is not indicated until age 40.
2. Obtain a fasting plasma glucose or hemoglobin A1c. (correct answer)
3. Recommend diet and exercise, and re-evaluate in one year.
4. Order a 2-hour oral glucose tolerance test.

Explanation: The 2021 USPSTF guidelines recommend screening for prediabetes and type 2 diabetes in adults aged 35 to 70 years who are overweight or obese (BMI ≥ 25 kg/m² or ≥ 23 kg/m² in Asian Americans). This patient is 36 years old and has a BMI of 31 kg/m², so he meets the criteria for screening. Appropriate screening tests include hemoglobin A1c, fasting plasma glucose, or an oral glucose tolerance test.

Question 12

1. Obtain a chest x-ray now and annually, as it has a lower radiation dose.
2. Proceed with an annual low-dose chest computed tomography (CT) scan. (correct answer)
3. Defer screening as he quit smoking more than 10 years ago.
4. Advise against screening due to his limited life expectancy from COPD.

Explanation: The US Preventive Services Task Force (USPSTF) recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years. This patient is 62 years old, has a 35-pack-year history, and quit 12 years ago, meeting all criteria for screening.

Question 13

1. Annual guaiac-based fecal occult blood test (gFOBT) with flexible sigmoidoscopy every 5 years.
2. Annual fecal immunochemical test (FIT). (correct answer)
3. Colonoscopy now, as it is the most sensitive test available.
4. Defer screening until age 60 due to her chronic kidney disease.

Explanation: For an average-risk individual, several colorectal cancer screening strategies are acceptable. Given the patient's anxiety about colonoscopy and her CKD (which can make aggressive bowel preps challenging), a high-quality stool-based test is an excellent first-tier alternative. The annual fecal immunochemical test (FIT) is a recommended, non-invasive option. If positive, it would be followed by a diagnostic colonoscopy.

Question 14

1. Advise against screening, as the potential harms outweigh the benefits.
2. Immediately order a PSA level, as he has multiple risk factors.
3. Discuss the potential benefits and harms of screening to facilitate a shared decision. (correct answer)
4. Refer him directly to a urologist to discuss screening options.

Explanation: For men aged 55 to 69 years, the USPSTF gives a Grade C recommendation for prostate cancer screening with PSA, meaning the decision should be individualized. The most appropriate action is for the primary care physician to engage in shared decision-making, discussing the potential benefits (small reduction in mortality) and harms (false positives, overdiagnosis, complications of treatment) to help the patient make an informed choice that aligns with his values and preferences. His risk factors (age, race, family history) make this conversation particularly important.

Question 15

1. Administer pneumococcal conjugate vaccine 20-valent (PCV20) alone. (correct answer)
2. Administer pneumococcal polysaccharide vaccine 23-valent (PPSV23) alone.
3. No pneumococcal vaccine is indicated until he reaches age 65.
4. Advise him to quit smoking first, then administer the vaccine later.

Explanation: The ACIP recommends pneumococcal vaccination for adults aged 19-64 with certain underlying medical conditions or risk factors, which include cigarette smoking. For a vaccine-naive individual in this category, the current recommendation is to administer either a single dose of PCV20 or a single dose of PCV15 followed by a dose of PPSV23 at least one year later. Administering PCV20 alone is a correct and complete strategy.

Question 16

1. Reassure him that no screening is needed as he is functionally asymptomatic.
2. Advise him to purchase over-the-counter reading glasses to see if they help.
3. Immediately refer him to an ophthalmologist for a comprehensive eye exam.
4. Formally assess visual acuity in the office using a Snellen chart. (correct answer)

Explanation: Vision screening questions on the USMLE Step 3 test your understanding of appropriate primary care evaluation before making referral decisions. When patients present with potential vision changes, you must first establish baseline function through objective testing. The correct approach here is D) Formally assess visual acuity in the office using a Snellen chart. Before making any recommendations about this patient's vision concerns, you need objective data. The wife's observation of increased squinting suggests possible vision changes, and at age 75, this patient is at higher risk for conditions like macular degeneration, glaucoma, and cataracts. A Snellen chart assessment takes minutes, provides standardized measurement, and guides your next steps based on actual findings rather than assumptions. A) Reassurance without screening ignores a potentially significant symptom. "Functionally asymptomatic" isn't accurate when someone is squinting more to read - this suggests compensatory behavior for declining vision. B) Recommending over-the-counter reading glasses bypasses proper evaluation. While presbyopia is common at this age, squinting could indicate other serious conditions that require professional assessment. C) Immediate ophthalmology referral jumps ahead without basic evaluation. While this patient will likely need eye care given his age and symptoms, primary care physicians should first document baseline visual acuity to provide meaningful information to the specialist and determine urgency. Study tip: For USMLE Step 3, remember the primary care principle: assess before you refer. Simple office-based tests (like Snellen charts) should precede specialist referrals when the clinical picture isn't immediately clear.

Question 17

1. No further screening is needed based on his reported moderate use.
2. Ask the CAGE questions, as they are the standard for alcohol screening.
3. Order a panel of liver function tests and a gamma-glutamyl transferase (GGT).
4. Administer a validated screening questionnaire such as the AUDIT-C. (correct answer)

Explanation: Alcohol screening is a cornerstone of preventive care that should be performed universally in primary care settings, regardless of a patient's self-reported drinking patterns. The key principle is that brief, validated screening tools can identify unhealthy alcohol use that patients might not volunteer or fully recognize. The AUDIT-C (Alcohol Use Disorders Identification Test-Consumption) is a 3-question validated screening tool recommended by the USPSTF for all adults. It's designed to detect the full spectrum of unhealthy alcohol use, from risky drinking patterns to alcohol use disorders. Even patients who report seemingly moderate consumption may have concerning patterns that warrant intervention, making systematic screening essential. Choice A is incorrect because universal screening is recommended regardless of reported use patterns. Patients often underreport consumption or may not recognize problematic patterns. Choice B is wrong because CAGE questions focus primarily on alcohol dependence and miss risky drinking that hasn't yet caused major consequences. The CAGE has largely been superseded by more sensitive tools like the AUDIT-C. Choice C is inappropriate as a screening tool because liver function tests lack sensitivity for detecting unhealthy alcohol use and are better suited for monitoring known alcohol-related liver disease. For USMLE Step 3, remember that preventive care questions often test your knowledge of evidence-based screening recommendations. When you see alcohol screening scenarios, think "universal screening with validated tools" rather than relying on clinical judgment alone or using less sensitive methods like laboratory tests.

Question 18

1. No STI screening is needed as she is over age 24 and asymptomatic.
2. Perform a Pap test with HPV co-testing only.
3. Screen for syphilis and HIV only.
4. Screen for chlamydia and gonorrhea. (correct answer)

Explanation: When you encounter STI screening questions on Step 3, focus on risk factors and current guidelines rather than just symptoms, since many STIs are asymptomatic. This 28-year-old woman has clear risk factors for chlamydia and gonorrhea: she's sexually active, has had multiple recent partners, and uses condoms inconsistently. Current CDC and USPSTF guidelines recommend annual chlamydia and gonorrhea screening for all sexually active women under 25, and for women 25 and older who have risk factors like multiple partners or inconsistent condom use. Since she fits both criteria perfectly, screening for these infections is most appropriate. Let's examine why the other options fall short: Option A is incorrect because age alone doesn't eliminate the need for STI screening when risk factors are present. The "asymptomatic" detail is actually irrelevant since most chlamydia and gonorrhea infections are asymptomatic. Option B focuses only on cervical cancer screening (Pap/HPV), which follows different guidelines based on age and screening history. While she may need cervical cancer screening, it doesn't address her STI risk factors. Option C suggests screening for syphilis and HIV only. While these might be considered given her risk factors, chlamydia and gonorrhea are far more common and have clearer screening recommendations for her demographic and risk profile. Remember for Step 3: STI screening decisions depend on age, sexual activity, and risk factors—not symptoms. Chlamydia and gonorrhea screening has the most straightforward, evidence-based guidelines for sexually active women with risk factors.

Question 19

1. Order a one-time abdominal ultrasound due to her smoking and family history.
2. Advise that routine screening is not recommended. (correct answer)
3. Order an abdominal CT angiogram for more detailed imaging.
4. Refer her to vascular surgery for a screening consultation.

Explanation: The USPSTF recommends a one-time screening for AAA by ultrasonography in men aged 65 to 75 years who have ever smoked. However, for women, the USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for women who have ever smoked (I statement) and recommends against routine screening in women who have never smoked (D recommendation). Therefore, routine screening is not recommended for her based on current guidelines.

Question 20

1. 10 years.
2. 7 years.
3. 3 years. (correct answer)
4. 1 year.

Explanation: The follow-up interval after polypectomy depends on the number, size, and histology of the adenomas found. An adenoma ≥10 mm (1.0 cm) is considered an advanced adenoma. According to the U.S. Multi-Society Task Force on Colorectal Cancer guidelines, patients with an advanced adenoma should have their next surveillance colonoscopy in 3 years. The presence of a second, small adenoma does not change this recommendation.