USMLE Step 2 CK Practice Questions
This is a free 15-question sampler of USMLE Step 2 CK style clinical questions, written by the StudyPDF team. It covers internal medicine, surgery, pediatrics, obstetrics and gynecology, psychiatry, screening and prevention, ethics and patient safety, and the biostatistics you use at the bedside, mixing multiple choice, select all that apply and fill in the blank. Answer all 15 questions, then check your score and read the explanation for every question.
A 72-year-old man reports two episodes of syncope while climbing stairs. Examination shows a crescendo-decrescendo systolic murmur at the right upper sternal border that radiates to both carotids, and the carotid upstroke is slow and low in volume. Which diagnosis best explains these findings?
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All 15 questions at a glance
Prefer to read before you play? Every question in the sampler is listed below. Answers and explanations stay collapsed until you open them.
1. A 72-year-old man reports two episodes of syncope while climbing stairs. Examination shows a crescendo-decrescendo systolic murmur at the right upper sternal border that radiates to both carotids, and the carotid upstroke is slow and low in volume. Which diagnosis best explains these findings?
- A. Mitral regurgitation
- B. Hypertrophic cardiomyopathy
- C. Aortic regurgitation
- D. Aortic stenosis
Show answer and explanation
Answer: D. Aortic stenosis
A slow, low volume carotid upstroke with a systolic ejection murmur radiating to the carotids points to a fixed obstruction at the aortic valve, and exertional syncope means the stenosis is severe enough that cardiac output cannot rise with demand. Mitral regurgitation gives a holosystolic murmur at the apex that radiates to the axilla, and aortic regurgitation is diastolic with a bounding rather than a weak pulse. Hypertrophic cardiomyopathy can sound similar, but its murmur gets louder with Valsalva while the aortic stenosis murmur softens, because less preload means less flow across a fixed valve.
2. A test with a sensitivity of 95 percent and a specificity of 70 percent was validated in a referral clinic. It is now used to screen a general population where the disease is far less common. Which value falls the most in the new setting?
- A. Sensitivity
- B. Specificity
- C. Positive predictive value
- D. Negative predictive value
Show answer and explanation
Answer: C. Positive predictive value
Sensitivity and specificity describe how the test behaves in people who do and do not have the disease, so they do not move when prevalence changes. Predictive values do. When prevalence drops, most positives are now false positives, so positive predictive value falls while negative predictive value rises. This is why a test that looks convincing in a specialty clinic can generate mostly false alarms when it is turned into a population screen.
3. Complete the sentence.
In a trial, the event rate is 20 percent in the control group and 15 percent in the treatment group. The absolute risk reduction is 5 percent, so the number needed to treat is _____.
Options for blank 1: 4, 5, 20, 100
Show answer and explanation
Answer: 20
Number needed to treat is 1 divided by the absolute risk reduction, so 1 divided by 0.05 gives 20. Relative risk reduction for the same numbers is 25 percent, which sounds far more impressive from the same data, and that gap is exactly why trials are often reported in relative terms. Always convert to absolute risk reduction before you judge how much a treatment actually buys.
4. Screening recommendations usually specify an age to stop as well as an age to start. What is the main reason for the upper age limit?
- A. Older adults cannot tolerate the screening test
- B. Disease incidence falls sharply with age
- C. Insurance stops covering the test
- D. The benefit of screening appears only after years, so a person with limited life expectancy takes on the harms without living long enough to gain
Show answer and explanation
Answer: D. The benefit of screening appears only after years, so a person with limited life expectancy takes on the harms without living long enough to gain
Screening harms are immediate: false positives, biopsies, overdiagnosis and the treatment that follows it. The benefit, fewer deaths from the disease, arrives years later. When remaining life expectancy is shorter than that lag, the arithmetic turns negative. Incidence of most screened cancers actually rises with age rather than falling, which is why the stopping rule is about life expectancy and comorbidity, not about age alone.
5. Which feature best distinguishes preeclampsia from chronic hypertension in a pregnant patient?
- A. Blood pressure elevation documented before 20 weeks of gestation
- B. A family history of hypertension
- C. New onset hypertension after 20 weeks of gestation
- D. Hypertension that persists more than 12 weeks after delivery
Show answer and explanation
Answer: C. New onset hypertension after 20 weeks of gestation
The dividing line is timing. Hypertension present before 20 weeks, or still present more than 12 weeks after delivery, is chronic hypertension. New hypertension after 20 weeks with proteinuria or with end organ dysfunction such as thrombocytopenia, elevated transaminases, renal impairment, pulmonary edema or new neurologic symptoms is preeclampsia. The two can coexist, which is called preeclampsia superimposed on chronic hypertension, and that combination raises risk more than either alone.
6. Which findings belong to the diagnostic picture of a manic episode?
Select all that apply.
- A. A decreased need for sleep with normal or high energy the next day
- B. Flight of ideas or racing thoughts
- C. Psychomotor retardation with hypersomnia
- D. An increase in goal directed activity or agitation
- E. Anhedonia present nearly every day for two weeks
Show answer and explanation
Answer: A. A decreased need for sleep with normal or high energy the next day, B. Flight of ideas or racing thoughts, D. An increase in goal directed activity or agitation
A manic episode needs a distinct period of elevated, expansive or irritable mood together with increased activity or energy, plus symptoms such as decreased need for sleep, racing thoughts, distractibility, inflated self esteem, pressured speech or risky goal directed behavior. Decreased need for sleep is not the same as insomnia: the patient sleeps little and still feels fine. Psychomotor retardation with hypersomnia and two weeks of anhedonia describe a major depressive episode, which is the other pole and not part of mania.
7. A 9-month-old has sudden episodes of crying while drawing his knees up, alternating with periods of lethargy. Examination reveals a sausage shaped mass in the right abdomen and a stool sample mixed with blood and mucus. Which is the most appropriate next diagnostic step?
- A. Abdominal ultrasound
- B. Upper gastrointestinal contrast series
- C. CT of the abdomen with contrast
- D. Colonoscopy
Show answer and explanation
Answer: A. Abdominal ultrasound
The picture is classic for intussusception, which peaks between about 6 and 36 months. Ultrasound is the first line study because it is fast, needs no radiation and shows the telescoped bowel as a target or donut on cross section. CT would answer the question too but costs radiation in an infant, an upper GI series looks at the wrong segment, and colonoscopy has no diagnostic role here.
8. Complete the sentence.
The Apgar score rates a newborn's color, heart rate, reflex irritability, muscle tone and respiratory effort, and it is assigned at _____ minute and again at _____ minutes after birth.
Options for blank 1: 1, 2, 5
Options for blank 2: 3, 5, 10
Show answer and explanation
Answer: 1, 5
Five components are each scored 0, 1 or 2, for a total of 0 to 10, at 1 and 5 minutes. If the 5 minute score stays low, scoring is repeated at intervals while the infant is assessed. The score describes the newborn's condition and how it responds over time, and it is not what triggers resuscitation, which begins on clinical assessment without waiting for a number.
9. Three days after an open abdominal operation a patient has distension, nausea and no flatus. Bowel sounds are absent. An abdominal radiograph shows gas distributed evenly through the small bowel and the colon, with no transition point and no distal collapse. Which explanation fits best?
- A. Adhesive small bowel obstruction
- B. Postoperative ileus
- C. Sigmoid volvulus
- D. Perforated viscus
Show answer and explanation
Answer: B. Postoperative ileus
The discriminating detail is the pattern of gas. Mechanical obstruction produces dilated bowel proximally, a transition point and a collapsed segment beyond it. Ileus is a failure of coordinated motility along the whole tract, so gas sits everywhere including the colon with no transition. Volvulus gives a characteristic dilated closed loop, and a perforated viscus is suggested by free air under the diaphragm and peritoneal signs, neither of which is described here.
10. Which statements describe requirements for valid informed consent?
Select all that apply.
- A. The patient is told the nature and purpose of the proposed intervention
- B. Risks, expected benefits and the reasonable alternatives, including doing nothing, are disclosed
- C. The patient has decision making capacity and the decision is voluntary and free of coercion
- D. Consent is valid only if a family member countersigns the form
- E. A relative may override the refusal of an adult who has capacity
Show answer and explanation
Answer: A. The patient is told the nature and purpose of the proposed intervention, B. Risks, expected benefits and the reasonable alternatives, including doing nothing, are disclosed, C. The patient has decision making capacity and the decision is voluntary and free of coercion
Valid consent needs disclosure, capacity, voluntariness and comprehension, and the signed form is only evidence that the conversation happened. Alternatives, including no intervention at all, are part of the disclosure, because a patient cannot weigh an option they were never told about. A competent adult's decision does not require a relative's approval and cannot be overridden by one.
11. An adult patient with full decision making capacity refuses a blood transfusion on religious grounds and states clearly that she understands she may die without it. Which response is most appropriate?
- A. Seek a court order authorizing transfusion
- B. Ask her adult children to consent on her behalf
- C. Confirm that she understands the consequences and alternatives, then respect the refusal
- D. Wait until she loses consciousness and then transfuse
Show answer and explanation
Answer: C. Confirm that she understands the consequences and alternatives, then respect the refusal
An adult with capacity may refuse any intervention, including one that is life sustaining, and the reason for the refusal does not have to be one the clinician agrees with. The physician's job is to confirm capacity, make sure the refusal is informed and voluntary, document it, and continue offering the care the patient does accept. Surrogates and courts step in when capacity is absent, not to overrule a capacitated adult, and transfusing after she becomes unconscious would defeat a decision she made while capable.
12. According to Light's criteria, which findings identify a pleural effusion as an exudate?
Select all that apply.
- A. A pleural fluid to serum protein ratio above 0.5
- B. A pleural fluid to serum lactate dehydrogenase ratio above 0.6
- C. A pleural fluid lactate dehydrogenase above two thirds of the upper limit of normal for serum
- D. A pleural fluid glucose identical to the serum glucose
- E. An effusion occurring in decompensated heart failure
Show answer and explanation
Answer: A. A pleural fluid to serum protein ratio above 0.5, B. A pleural fluid to serum lactate dehydrogenase ratio above 0.6, C. A pleural fluid lactate dehydrogenase above two thirds of the upper limit of normal for serum
Light's criteria need only one of the three to be met for the fluid to count as an exudate, which makes them very sensitive and somewhat prone to labeling a transudate as an exudate. The distinction matters because it splits the differential: exudates come from inflammation, infection or malignancy that leaks protein across the pleura, while transudates come from pressure problems such as heart failure, cirrhosis or nephrotic syndrome. Fluid glucose equal to serum is unremarkable, and heart failure is the classic transudate.
13. Complete the sentence.
A diagnosis of schizophrenia requires continuous signs of the illness for at least _____ months, while a presentation that has lasted between one and six months is called _____.
Options for blank 1: 1, 3, 6
Options for blank 2: brief psychotic disorder, schizophreniform disorder, schizoaffective disorder
Show answer and explanation
Answer: 6, schizophreniform disorder
The psychotic disorders are separated mainly by duration. Under one month is brief psychotic disorder, one to six months is schizophreniform disorder, and six months or more of continuous signs, counting prodromal and residual periods, is schizophrenia, with at least one month of active symptoms inside that window. Schizoaffective disorder is defined differently: it needs a mood episode plus a period of psychosis lasting two weeks or more without prominent mood symptoms.
14. Which headache history feature most strongly suggests a secondary rather than a primary headache?
- A. A throbbing unilateral headache with photophobia that eases after sleep
- B. Sudden onset pain that reaches maximum intensity within a minute
- C. A bilateral band like pressure that builds through the workday
- D. Pain that improves after caffeine
Show answer and explanation
Answer: B. Sudden onset pain that reaches maximum intensity within a minute
A thunderclap headache, one that peaks within about a minute, is the classic red flag for subarachnoid hemorrhage and other vascular causes, and it warrants urgent evaluation rather than symptomatic treatment. Other red flags include a first severe headache after age 50, fever with neck stiffness, focal neurologic deficits, papilledema, pain that worsens with position or Valsalva, and headache in someone who is immunosuppressed or has cancer. The other three options describe familiar primary patterns, migraine and tension type headache.
15. Which set of laboratory findings best fits iron deficiency anemia?
- A. Low mean corpuscular volume, low ferritin, high total iron binding capacity
- B. Low mean corpuscular volume, high ferritin, low total iron binding capacity
- C. High mean corpuscular volume, normal ferritin, normal total iron binding capacity
- D. Normal mean corpuscular volume, low vitamin B12, high methylmalonic acid
Show answer and explanation
Answer: A. Low mean corpuscular volume, low ferritin, high total iron binding capacity
In iron deficiency the stores empty first, so ferritin falls, and the liver makes more transferrin to scavenge what iron is left, which raises total iron binding capacity. Red cells made without enough iron end up small, so the mean corpuscular volume drops. Anemia of chronic disease is the trap: it is also microcytic or normocytic, but ferritin is normal or high because it is an acute phase reactant and total iron binding capacity is low. The high volume and the B12 patterns point to macrocytic causes instead.
What Step 2 CK tests and why it now carries more weight
Step 2 CK is the clinical knowledge exam in the United States Medical Licensing Examination sequence, a joint program of the Federation of State Medical Boards and the National Board of Medical Examiners. In January 2022 Step 1 stopped reporting a three digit number and began reporting pass or fail only. Step 2 CK did not change, so it became the only numeric USMLE score most residency programs ever see. That single change is why this page exists.
The exam is a single day of multiple choice blocks, several hours long, and it is scored numerically. The item count, the block structure, the time per block and the current minimum passing score are set by the USMLE program and have been adjusted more than once, so read those numbers on usmle.org and in the current content outline rather than trusting a number from a forum post.
The content is clinical. Internal medicine carries the largest share, with surgery, pediatrics, obstetrics and gynecology and psychiatry filling most of the rest, plus health maintenance and screening, patient safety, ethics and communication, and applied biostatistics. Most items are vignettes that ask for a diagnosis, the next diagnostic step, the most likely mechanism, or how a result should change what you believe.
How to use this sampler and how to study the material
These 15 questions are built around the reasoning step rather than recall. They ask which finding narrows the differential, what the next diagnostic test buys you, which property of a test moves when prevalence moves, and how a duration criterion separates two psychiatric diagnoses. That is the habit Step 2 CK rewards, because a vignette usually hands you enough data to reach the answer if you know what each piece is for.
Take all 15 in one sitting without notes, then read the explanation for every question, including the ones you got right. Guessing correctly and knowing are different, and only the explanation tells you which one happened. Treat a wrong answer as a topic rather than a fact. If you missed the pleural fluid question and the anemia question, the lesson is that you read lab panels one value at a time instead of as a pattern.
One honest note. This page is exam practice written by the StudyPDF team from the published Step 2 CK content outline. It is not medical guidance and none of these are real exam items. Where a real vignette would ask you to pick a drug or a dose, this sampler asks about the reasoning instead.
How StudyPDF builds full practice tests from your own materials
Fifteen questions can show you where your clinical reasoning is thin. They cannot get you ready for a full day exam on their own, and a generic bank never matches the emphasis of the shelf you are sitting next month or the notes your own rotation gave you.
StudyPDF works from your material instead. You upload your Step 2 review book, your rotation notes, a lecture deck or the PDF handouts from your clerkship, and Bo, the study agent, builds full length practice tests from those exact pages. Every question is grounded in your material and every explanation cites where the answer came from, so you can jump straight to the page when something looks wrong. You can regenerate fresh tests as often as you want, narrow them to one area such as cardiology or obstetrics, and track which concepts you keep missing across attempts.
You do not need a document to start. If you have nothing to upload, name a topic instead, for example acid base disorders, antenatal screening or the ethics of surrogate decision making, and Bo writes a practice test from that. Starting is free.
Written by the StudyPDF team. Last updated 2026-08-19.