USMLE STEP 1 – PRACTICE QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
*CORE DOMAINS*
*• Pathology*
*• Pharmacology*
*• Physiology*
*• Microbiology*
*• Biochemistry*
*• Anatomy*
*• Behavioral Sciences*
*• Immunology*
*• Genetics*
*• Nutrition*
*INTRODUCTION*
The purpose of this assessment is to evaluate the foundational medical knowledge
and clinical reasoning skills essential for the practice of medicine. This exam
assesses a candidate's ability to apply basic science principles to clinical scenarios,
focusing on the mechanisms of disease, health maintenance, and therapeutic
,interventions. The structure utilizes multiple-choice and scenario-based questions
that mirror the complexity of actual medical practice. Emphasis is placed on real-
world application, diagnostic decision-making, and the integration of multidisciplinary
scientific concepts. This practice set serves as a comprehensive tool to ensure
readiness for professional licensure and high-stakes clinical environments.
SECTION ONE: QUESTIONS 1–100
1. A 45-year-old male presents with severe pain in his right great toe that began
suddenly overnight. Physical examination reveals erythema, warmth, and
exquisite tenderness at the first metatarsophalangeal joint. Synovial fluid
analysis shows needle-shaped, negatively birefringent crystals. Which of the
following is the most appropriate initial treatment for this patient’s acute
condition?
A. Allopurinol
B. Probenecid
🟢 C. Indomethacin
D. Febuxostat
,🔴 RATIONALE: The patient is experiencing an acute gouty arthritis attack.
Nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin are first-line for
acute attacks. Allopurinol and febuxostat are used for long-term urate-lowering
therapy but can worsen an acute flare if initiated during the attack.
2. A 62-year-old female with a history of hypertension and chronic kidney disease
presents with fatigue. Laboratory studies show a hemoglobin of 9.2 g/dL and a
hematocrit of 28%. Her erythropoietin levels are inappropriately low. Which of
the following cellular structures is the primary site of erythropoietin production in
this patient?
🟢 A. Peritubular capillaries of the renal cortex
B. Juxtaglomerular cells
C. Proximal convoluted tubule cells
D. Macula densa
🔴 RATIONALE: Erythropoietin (EPO) is primarily synthesized by interstitial cells in
the peritubular capillary bed of the renal cortex and outer medulla in response to
hypoxia. Chronic kidney disease leads to the destruction of these cells, resulting in
normocytic anemia.
, 3. A 4-year-old boy is brought to the pediatrician due to developmental delay and a
musty body odor. His mother notes that he frequently bites his lips and fingers.
Laboratory testing reveals an inability to convert phenylalanine to tyrosine.
Which of the following enzymes is most likely deficient?
A. Tyrosinase
🟢 B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Branched-chain alpha-keto acid dehydrogenase
🔴 RATIONALE: Phenylketonuria (PKU) is most commonly caused by a deficiency in
phenylalanine hydroxylase. This leads to an accumulation of phenylalanine and a
deficiency of tyrosine, resulting in intellectual disability, seizures, and a characteristic
musty odor.
4. A 28-year-old woman at 32 weeks gestation presents with a headache and
blurred vision. Her blood pressure is 165/110 mmHg. Urinalysis shows 3+
proteinuria. Which of the following is the most appropriate immediate medication
to prevent seizures in this patient?
ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
*CORE DOMAINS*
*• Pathology*
*• Pharmacology*
*• Physiology*
*• Microbiology*
*• Biochemistry*
*• Anatomy*
*• Behavioral Sciences*
*• Immunology*
*• Genetics*
*• Nutrition*
*INTRODUCTION*
The purpose of this assessment is to evaluate the foundational medical knowledge
and clinical reasoning skills essential for the practice of medicine. This exam
assesses a candidate's ability to apply basic science principles to clinical scenarios,
focusing on the mechanisms of disease, health maintenance, and therapeutic
,interventions. The structure utilizes multiple-choice and scenario-based questions
that mirror the complexity of actual medical practice. Emphasis is placed on real-
world application, diagnostic decision-making, and the integration of multidisciplinary
scientific concepts. This practice set serves as a comprehensive tool to ensure
readiness for professional licensure and high-stakes clinical environments.
SECTION ONE: QUESTIONS 1–100
1. A 45-year-old male presents with severe pain in his right great toe that began
suddenly overnight. Physical examination reveals erythema, warmth, and
exquisite tenderness at the first metatarsophalangeal joint. Synovial fluid
analysis shows needle-shaped, negatively birefringent crystals. Which of the
following is the most appropriate initial treatment for this patient’s acute
condition?
A. Allopurinol
B. Probenecid
🟢 C. Indomethacin
D. Febuxostat
,🔴 RATIONALE: The patient is experiencing an acute gouty arthritis attack.
Nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin are first-line for
acute attacks. Allopurinol and febuxostat are used for long-term urate-lowering
therapy but can worsen an acute flare if initiated during the attack.
2. A 62-year-old female with a history of hypertension and chronic kidney disease
presents with fatigue. Laboratory studies show a hemoglobin of 9.2 g/dL and a
hematocrit of 28%. Her erythropoietin levels are inappropriately low. Which of
the following cellular structures is the primary site of erythropoietin production in
this patient?
🟢 A. Peritubular capillaries of the renal cortex
B. Juxtaglomerular cells
C. Proximal convoluted tubule cells
D. Macula densa
🔴 RATIONALE: Erythropoietin (EPO) is primarily synthesized by interstitial cells in
the peritubular capillary bed of the renal cortex and outer medulla in response to
hypoxia. Chronic kidney disease leads to the destruction of these cells, resulting in
normocytic anemia.
, 3. A 4-year-old boy is brought to the pediatrician due to developmental delay and a
musty body odor. His mother notes that he frequently bites his lips and fingers.
Laboratory testing reveals an inability to convert phenylalanine to tyrosine.
Which of the following enzymes is most likely deficient?
A. Tyrosinase
🟢 B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Branched-chain alpha-keto acid dehydrogenase
🔴 RATIONALE: Phenylketonuria (PKU) is most commonly caused by a deficiency in
phenylalanine hydroxylase. This leads to an accumulation of phenylalanine and a
deficiency of tyrosine, resulting in intellectual disability, seizures, and a characteristic
musty odor.
4. A 28-year-old woman at 32 weeks gestation presents with a headache and
blurred vision. Her blood pressure is 165/110 mmHg. Urinalysis shows 3+
proteinuria. Which of the following is the most appropriate immediate medication
to prevent seizures in this patient?
