NBME CBSE ACTUAL TEST
QUESTIONS AND ANSWERS
2024/2026(Quiz bank with all the
correct answers)(usmle step
1)Medical examination NBME CBSE
Question 1: Pharmacology / Cardiology
A 62-year-old woman with hypertension is started on a new medication. One week
later, she presents with fatigue and palpitations. Her ECG shows prominent U
waves and a prolonged QT interval. Which electrolyte imbalance is the most likely
cause of her ECG findings, and which medication class is the most common
culprit?
• A) Hyperkalemia, ACE inhibitors
• B) Hypokalemia, Thiazide diuretics
• C) Hypocalcemia, Beta-blockers
• D) Hypermagnesemia, Loop diuretics
Correct ,,,answer,,,: B
Rationale: Thiazide diuretics can cause hypokalemia. Classic ECG findings in
hypokalemia include ST depression, flattened T waves, and prominent U waves,
which are best seen in the precordial leads.
Question 2: Microbiology
A 45-year-old man with diabetes presents with fever, productive cough, and "rusty"
sputum. A chest x-ray shows right lower lobe consolidation. A gram stain of his
,sputum shows gram-positive, lancet-shaped diplococci. What is the most likely
organism?
• A) Staphylococcus aureus
• B) Klebsiella pneumoniae
• C) Streptococcus pneumoniae
• D) Moraxella catarrhalis
Correct ,,,answer,,,: C
Rationale: Streptococcus pneumoniae is a gram-positive, lancet-shaped
diplococcus. It is the most common cause of community-acquired pneumonia and
classically presents with lobar consolidation and "rusty" sputum.
Question 3: Immunology
A 30-year-old woman presents with a facial rash, arthritis, and pleuritic chest pain.
Her ANA and anti-dsDNA antibodies are positive. The renal injury associated with
this condition is primarily mediated by which type of hypersensitivity reaction?
• A) Type I (Anaphylactic)
• B) Type II (Cytotoxic)
• C) Type III (Immune Complex)
• D) Type IV (Delayed-type)
Correct ,,,answer,,,: C
Rationale: Systemic lupus erythematosus (SLE) is the classic example of a Type
III hypersensitivity disorder. In the kidneys, circulating immune complexes (anti-
dsDNA antibodies and DNA antigens) deposit in the glomeruli, leading to
complement activation and inflammation.
Question 4: Pathology
A 70-year-old man dies in a motor vehicle collision. He was being evaluated for
occult blood in his stool. A photograph of his transverse colon during autopsy
shows a small, pedunculated mass. Histologically, the mass is composed of
dysplastic epithelium forming tubular structures. What is the diagnosis?
• A) Hyperplastic polyp
, • B) Tubular adenoma
• C) Villous adenoma
• D) Adenocarcinoma
Correct ,,,answer,,,: B
Rationale: A tubular adenoma is a precancerous polyp of the colon. It is
characterized by a pedunculated (stalked) growth and a histology showing
dysplastic, tubular glands. It can be a source of occult blood.
Question 5: Microbiology
A 24-year-old man presents with small, painful, fluid-filled blisters on his penis.
He reports having unprotected sex three days ago. A Tzanck smear of the blister
base shows multinucleated giant cells. What is the most likely causative agent?
• A) Treponema pallidum
• B) Human papillomavirus (HPV)
• C) Herpes simplex virus type 2 (HSV-2)
• D) Chlamydia trachomatis
Correct ,,,answer,,,: C
Rationale: HSV-2 typically causes painful genital vesicles and ulcers. The Tzanck
smear finding of multinucleated giant cells is a classic rapid diagnostic feature of
a herpes virus infection.
Question 6: Biostatistics
A cohort study of elderly women examines the association between regular
exercise and the risk of hip fracture. The relative risk (RR) for hip fractures among
those who exercise regularly is 1.2, with a 95% confidence interval (CI) of 1.1 to
1.8. Based on this data, which conclusion about the effect of exercise on hip
fracture risk is most accurate?
• A) There is no association between exercise and hip fracture risk.
• B) Exercise is associated with a statistically significant overall increase in
risk.
, • C) Exercise is associated with a statistically significant overall decrease in
risk.
• D) The study is not powerful enough to draw a conclusion.
Correct ,,,answer,,,: B
Rationale: The RR is greater than 1.0 (1.2), suggesting an increased risk. The 95%
CI does not cross 1.0 (it goes from 1.1 to 1.8), which means this result is
statistically significant at the p<0.05 level. Therefore, the study concludes that
exercise is associated with a small but statistically significant increase in the risk of
hip fracture.
Question 7: Pharmacology
A 51-year-old man with a history of coronary artery disease and erectile
dysfunction presents to the emergency department with his wife. She reports he
took one of his friend's sildenafil (Viagra) pills about four hours ago. He now has a
crushing substernal chest. What concurrent medication, if also taken by the patient,
would most strongly suggest the mechanism of this emergency?
• A) Lisinopril
• B) Metformin
• C) Nitroglycerin
• D) Atorvastatin
Correct ,,,answer,,,: C
Rationale: Sildenafil potentiates the hypotensive effects of nitrates by amplifying
the nitric oxide-cGMP pathway. Concurrent use can lead to severe, life-threatening
hypotension and myocardial ischemia. The patient's history of coronary artery
disease makes it very likely he has a prescription for nitroglycerin.
Question 8: Reproductive/Endocrine
A 17-year-old gymnast comes to the clinic due to lack of menstrual periods for the
past 6 months. She has a BMI of 15 kg/m² and admits to severely restricting her
food intake. Her FSH and LH levels are low. What is the most likely diagnosis?
• A) Polycystic ovary syndrome (PCOS)
• B) Primary ovarian insufficiency
QUESTIONS AND ANSWERS
2024/2026(Quiz bank with all the
correct answers)(usmle step
1)Medical examination NBME CBSE
Question 1: Pharmacology / Cardiology
A 62-year-old woman with hypertension is started on a new medication. One week
later, she presents with fatigue and palpitations. Her ECG shows prominent U
waves and a prolonged QT interval. Which electrolyte imbalance is the most likely
cause of her ECG findings, and which medication class is the most common
culprit?
• A) Hyperkalemia, ACE inhibitors
• B) Hypokalemia, Thiazide diuretics
• C) Hypocalcemia, Beta-blockers
• D) Hypermagnesemia, Loop diuretics
Correct ,,,answer,,,: B
Rationale: Thiazide diuretics can cause hypokalemia. Classic ECG findings in
hypokalemia include ST depression, flattened T waves, and prominent U waves,
which are best seen in the precordial leads.
Question 2: Microbiology
A 45-year-old man with diabetes presents with fever, productive cough, and "rusty"
sputum. A chest x-ray shows right lower lobe consolidation. A gram stain of his
,sputum shows gram-positive, lancet-shaped diplococci. What is the most likely
organism?
• A) Staphylococcus aureus
• B) Klebsiella pneumoniae
• C) Streptococcus pneumoniae
• D) Moraxella catarrhalis
Correct ,,,answer,,,: C
Rationale: Streptococcus pneumoniae is a gram-positive, lancet-shaped
diplococcus. It is the most common cause of community-acquired pneumonia and
classically presents with lobar consolidation and "rusty" sputum.
Question 3: Immunology
A 30-year-old woman presents with a facial rash, arthritis, and pleuritic chest pain.
Her ANA and anti-dsDNA antibodies are positive. The renal injury associated with
this condition is primarily mediated by which type of hypersensitivity reaction?
• A) Type I (Anaphylactic)
• B) Type II (Cytotoxic)
• C) Type III (Immune Complex)
• D) Type IV (Delayed-type)
Correct ,,,answer,,,: C
Rationale: Systemic lupus erythematosus (SLE) is the classic example of a Type
III hypersensitivity disorder. In the kidneys, circulating immune complexes (anti-
dsDNA antibodies and DNA antigens) deposit in the glomeruli, leading to
complement activation and inflammation.
Question 4: Pathology
A 70-year-old man dies in a motor vehicle collision. He was being evaluated for
occult blood in his stool. A photograph of his transverse colon during autopsy
shows a small, pedunculated mass. Histologically, the mass is composed of
dysplastic epithelium forming tubular structures. What is the diagnosis?
• A) Hyperplastic polyp
, • B) Tubular adenoma
• C) Villous adenoma
• D) Adenocarcinoma
Correct ,,,answer,,,: B
Rationale: A tubular adenoma is a precancerous polyp of the colon. It is
characterized by a pedunculated (stalked) growth and a histology showing
dysplastic, tubular glands. It can be a source of occult blood.
Question 5: Microbiology
A 24-year-old man presents with small, painful, fluid-filled blisters on his penis.
He reports having unprotected sex three days ago. A Tzanck smear of the blister
base shows multinucleated giant cells. What is the most likely causative agent?
• A) Treponema pallidum
• B) Human papillomavirus (HPV)
• C) Herpes simplex virus type 2 (HSV-2)
• D) Chlamydia trachomatis
Correct ,,,answer,,,: C
Rationale: HSV-2 typically causes painful genital vesicles and ulcers. The Tzanck
smear finding of multinucleated giant cells is a classic rapid diagnostic feature of
a herpes virus infection.
Question 6: Biostatistics
A cohort study of elderly women examines the association between regular
exercise and the risk of hip fracture. The relative risk (RR) for hip fractures among
those who exercise regularly is 1.2, with a 95% confidence interval (CI) of 1.1 to
1.8. Based on this data, which conclusion about the effect of exercise on hip
fracture risk is most accurate?
• A) There is no association between exercise and hip fracture risk.
• B) Exercise is associated with a statistically significant overall increase in
risk.
, • C) Exercise is associated with a statistically significant overall decrease in
risk.
• D) The study is not powerful enough to draw a conclusion.
Correct ,,,answer,,,: B
Rationale: The RR is greater than 1.0 (1.2), suggesting an increased risk. The 95%
CI does not cross 1.0 (it goes from 1.1 to 1.8), which means this result is
statistically significant at the p<0.05 level. Therefore, the study concludes that
exercise is associated with a small but statistically significant increase in the risk of
hip fracture.
Question 7: Pharmacology
A 51-year-old man with a history of coronary artery disease and erectile
dysfunction presents to the emergency department with his wife. She reports he
took one of his friend's sildenafil (Viagra) pills about four hours ago. He now has a
crushing substernal chest. What concurrent medication, if also taken by the patient,
would most strongly suggest the mechanism of this emergency?
• A) Lisinopril
• B) Metformin
• C) Nitroglycerin
• D) Atorvastatin
Correct ,,,answer,,,: C
Rationale: Sildenafil potentiates the hypotensive effects of nitrates by amplifying
the nitric oxide-cGMP pathway. Concurrent use can lead to severe, life-threatening
hypotension and myocardial ischemia. The patient's history of coronary artery
disease makes it very likely he has a prescription for nitroglycerin.
Question 8: Reproductive/Endocrine
A 17-year-old gymnast comes to the clinic due to lack of menstrual periods for the
past 6 months. She has a BMI of 15 kg/m² and admits to severely restricting her
food intake. Her FSH and LH levels are low. What is the most likely diagnosis?
• A) Polycystic ovary syndrome (PCOS)
• B) Primary ovarian insufficiency
