Immunology USMLE Step 1 Practice Questions
74 board-style USMLE Step 1 questions in Microbiology/Immunology. Each question shows the correct answer; create a free account for the full explanation and adaptive practice.
- USMLE Step 1 · medium1. An investigator is studying the immunologic response to a Staphylococcus aureus toxin in a mouse model. Fourteen days after injecting mice with this toxin, he isolates antibodie…
- USMLE Step 1 · medium2. An investigator is developing a new vaccine that offers lifelong immunity against a certain disease. After injecting the agent, the immune response is recorded by measuring vacc…
- USMLE Step 1 · medium3. A 58-year-old woman comes to the physician for evaluation of worsening fatigue for 1 week. She also has a 1-year history of hand pain and stiffness. Four months ago, she started…
- USMLE Step 1 · hard4. A 76-year-old woman comes to the physician because of a sudden loss of vision in her right eye for 10 minutes that morning, which subsided spontaneously. Over the past 2 months,…
- USMLE Step 1 · medium5. A 65-year-old man with a past medical history of well-controlled hypertension on lisinopril presents for annual preventive care. He reports feeling well with no acute complaints…
- USMLE Step 1 · medium6. A 23-year-old male college student presents with a 6-month history of excessive daytime somnolence despite obtaining 7–8 hours of nocturnal sleep. He reports sudden, irresistibl…
- USMLE Step 1 · hard7. A 76-year-old woman presents to the clinic with a 2-month history of temporal headaches, scalp tenderness, and jaw claudication while chewing. She reports amaurosis fugax of the…
- USMLE Step 1 · medium8. A 26-year-old woman presents with high fever (39.8°C), diffuse erythematous rash, vomiting, and hypotension (88/52 mmHg) two days after inserting a superabsorbent tampon. Vital…
- USMLE Step 1 · medium9. A 26-year-old man presents with fever (38.8°C), productive cough, and malaise 2 weeks after cleaning a chicken coop in the Ohio River valley. Vital signs show BP 118/76, HR 92,…
- USMLE Step 1 · medium10. A 42-year-old man with AIDS (CD4 count 35 cells/μL) presents with progressive headache, fever (38.9°C), and blurred vision for 2 weeks. Vital signs show BP 118/76, HR 98, RR 16,…
- USMLE Step 1 · medium11. A 62-year-old man with no recent medical care presents with progressive jaw stiffness and painful muscle spasms beginning one week after a puncture wound to his foot from a barn…
- USMLE Step 1 · medium12. A 48-year-old woman receives cosmetic botulinum toxin injections. Five days later, she develops diplopia, ptosis, dysphagia, and descending flaccid paralysis. Vital signs: BP 12…
- USMLE Step 1 · medium13. A 6-year-old boy presents with nonbloody watery diarrhea after visiting relatives in a rural area. Vital signs show HR 110/min, BP 95/60 mmHg, temperature 37.2°C, and mild dehyd…
- USMLE Step 1 · medium14. A 27-year-old woman presents with acute watery diarrhea beginning 2 days after arriving in Mexico. Vital signs: BP 118/76, HR 88, RR 16, Temp 37.2°C, SpO2 98% on room air. She d…
- USMLE Step 1 · medium15. A 4 month old infant with no prior vaccinations is brought to clinic because of paroxysmal coughing spells followed by inspiratory whooping and posttussive vomiting. The respons…
- USMLE Step 1 · easy16. A 6-year-old unvaccinated boy presents with fever (39.2°C), sore throat, and progressive stridor. Vital signs show HR 118/min, RR 28/min, BP 102/68 mmHg, SpO2 94% on room air. E…
- USMLE Step 1 · hard17. A 42-year-old man who works in a wool processing factory presents with a painless black eschar on his forearm surrounded by marked edema. Vital signs show BP 128/82 mmHg, HR 92/…
- USMLE Step 1 · hard18. A 45-year-old man with rheumatoid arthritis receives an experimental fusion protein that blocks B7-CD28 interaction on antigen-presenting cells. His vital signs are stable (BP 1…
- USMLE Step 1 · medium19. A 52-year-old man presents with fever (38.5°C), malaise, and cough for 3 days. Viral PCR is positive. Physical examination reveals decreased breath sounds bilaterally; chest X-r…
- USMLE Step 1 · medium20. A 17-year-old girl receives a tetanus booster immunization. Within 48 hours, she develops localized arm erythema (BP 118/76, HR 82, RR 16, Temp 38.2°C, SpO2 98%). Serum analysis…
- USMLE Step 1 · hard21. A 58 year old woman received a renal transplant 4 years ago. She now has slowly progressive hypertension and rising serum creatinine. Biopsy of the graft shows interstitial fibr…
- USMLE Step 1 · medium22. A 46-year-old man undergoes kidney transplantation. Two weeks post-operatively, he develops hypertension (BP 158/92 mmHg), tachycardia (HR 104/min), and malaise. Serum creatinin…
- USMLE Step 1 · easy23. A 22-year-old man presents with a pruritic vesicular rash on his forearms that developed 2 days after clearing brush in the woods. Vital signs are stable (BP 118/76, HR 88, RR 1…
- USMLE Step 1 · medium24. A 29-year-old man received antivenom following a rattlesnake bite 10 days ago. He now presents with fever (38.5°C), diffuse urticaria, and arthralgias. Vital signs show BP 128/8…