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 · hard49. A 3-month-old boy presents with severe watery diarrhea, diffuse dermatitis, and poor feeding for 2 weeks. Vital signs show HR 128/min, RR 32/min, temperature 37.2°C, and BP 85/5…
- USMLE Step 1 · hard50. A 12-year-old girl presents with recurrent oral candidiasis, muscle cramps, and fatigue. Vital signs show HR 98/min, BP 102/68 mmHg, RR 16/min, temperature 37.2°C. Laboratory st…
- USMLE Step 1 · medium51. A 23 year old woman comes to the emergency department with recurrent episodes of severe abdominal pain and swelling of the lips and tongue. She has no urticaria or pruritus. Sym…
- USMLE Step 1 · medium52. A 4-year-old girl presents with recurrent otitis media, pneumonia, and two episodes of septicemia since infancy. Vital signs show BP 95/60, HR 112, RR 24, Temp 38.2°C, SpO2 98%.…
- USMLE Step 1 · easy53. A 19-year-old college student presents with fever (39.8°C), headache, and nuchal rigidity. He was hospitalized twice within one year for meningococcal meningitis confirmed by CS…
- USMLE Step 1 · medium54. A 7 year old boy is seen for recurrent skin abscesses and repeated episodes of pneumonia. His parents say the abscesses are not very red or tender. He has chronic eczema and coa…
- USMLE Step 1 · medium55. A 2-year-old boy presents with recurrent otitis media, severe Pneumocystis jirovecii pneumonia (SpO2 88%), and chronic Cryptosporidium diarrhea. Vital signs show HR 115, RR 28,…
- USMLE Step 1 · medium56. A 14-month-old boy presents to the emergency department with bloody diarrhea and diffuse eczema. Parents report recurrent otitis media since infancy and note he bruises easily.…
- USMLE Step 1 · medium57. A 5 year old girl is evaluated for recurrent pyogenic infections and progressive difficulty walking. Her parents report that she bruises easily and that her hair and skin have a…
- USMLE Step 1 · easy58. A 2-week-old male newborn presents with fever (38.9°C), tachycardia (165 bpm), and omphalitis with erythematous umbilical skin that has separated incompletely. The mother denies…
- USMLE Step 1 · easy59. A 6-year-old boy presents with recurrent skin abscesses and pneumonia. Vital signs show HR 110/min, BP 105/68 mmHg, RR 22/min, temperature 38.2°C, SpO2 98% on room air. Prior cu…
- USMLE Step 1 · medium60. A 4 month old boy is hospitalized for persistent thrush, chronic diarrhea, and Pneumocystis jirovecii pneumonia. He has had poor weight gain since birth. Flow cytometry shows ma…
- USMLE Step 1 · easy61. A 2 month old boy has recurrent viral and fungal infections, difficulty feeding, and episodes of perioral twitching. He was born with a conotruncal cardiac defect. Physical exam…
- USMLE Step 1 · easy62. A 17 year old boy is evaluated for recurrent sinusitis and chronic watery diarrhea. He has had two prior episodes of Giardia lamblia infection. He is otherwise healthy. Serum im…
- USMLE Step 1 · easy63. A 9 month old boy is brought to the clinic for recurrent otitis media, sinus infections, and bacterial pneumonia after weaning from breastfeeding. He has had chronic diarrhea wi…
- USMLE Step 1 · medium64. A 4-year-old boy with recurrent Staphylococcus aureus and Streptococcus pneumoniae infections presents with fever (38.2°C), lymphadenopathy, and mild splenomegaly. Vital signs s…
- USMLE Step 1 · medium65. A 65-year-old male with hypertension (BP 142/88 mmHg, HR 98/min) undergoes coronary artery bypass surgery grafting the left internal mammary artery to the left main coronary art…
- USMLE Step 1 · medium66. A formula-fed, 1-month-old male is exposed to his sister with active varicella (vesicular rash, fever 38.5°C). Despite exposure, he remains asymptomatic with no cutaneous lesion…
- USMLE Step 1 · medium67. A 23-year-old female suffers from a condition in which her antibodies react with antigens present on the surface of cells. The mechanism of action involves complement fixation b…
- USMLE Step 1 · medium68. A 20-year-old male with stridor is brought to the emergency department by his girlfriend. He had been complaining of abdominal pain earlier in the day. Physical examination is s…
- USMLE Step 1 · medium69. After high-dose chemotherapy and irradiation, a 35-year-old female with acute myeloid leukemia in remission receives a bone marrow transplant from her HLA-matched brother. One w…
- USMLE Step 1 · medium70. A 3-year-old female presents with recurrent subcutaneous abscesses and furuncles. Vital signs show temperature 37.8°C, HR 98/min, BP 95/62 mmHg, RR 22/min, and SpO2 98% on room…
- USMLE Step 1 · medium71. A 54-year-old male with chronic renal failure receives a kidney transplant and begins cyclosporine immunosuppression. Six months later, he presents with progressive fatigue and…
- USMLE Step 1 · medium72. A 24-year-old female with a history of allergic rhinitis is involved in an automobile accident and sustains a splenic laceration. She undergoes abdominal surgery and is then tra…