An NBME-style question is a short clinical story with one job at the end. The story, the five letters, and the explanation are original StepLobe writing. The format asks you to use a timeline, a mechanism, or a constraint. It does not ask you to match a nickname to a disease name.
How the vignette is put together
Read a strong stem from top to bottom and you can retell it as a timeline. Age and setting come first. Then the symptom, how long it has lasted, and what changed. Then the exam, then the numbers. Later events stay later. In the first sample on this page, bleeding starts at home, the low blood pressure is measured on arrival, the pressure recovers after fluids and blood, and the liver enzymes peak the next day and fall by day 10. That order is the question. A pile of classic adjectives, with the diagnosis hiding inside the adjectives, is a weaker kind of item.
The same rule is why these stems skip buzzwords. A buzzword lets you skip the story. If the stem named the enzyme, the lead-in would be a recall check. Here you get the time course of a reversible enzyme rise after a brief hypotensive hour, and you name the earliest cellular event. Lab rows work the same way: read the column the lead-in cares about. On the oxacillin item, the pair that stays resistant together is oxacillin and cefazolin. Penicillin G being resistant is true and is not the decisive line.
Where the second and third order live
The lead-in is the sentence that starts the actual task, usually with “Which.” A first-order lead-in asks for the diagnosis. A second-order lead-in asks for the mechanism, the nerve, the embryologic structure, the drug target, or the lab pattern that follows from a diagnosis you made silently. A third-order lead-in ties two of those together: why this finding changes that risk, or which structure explains both the imaging and the lab.
The oxacillin item does not ask you to name the organism. The culture already did that. It asks which resistance mechanism fits an isolate that ignores oxacillin and cefazolin and still dies with vancomycin. The eye item asks why the globes move forward, not the name of the thyroid disease. The infant item asks which embryologic tube stayed open, and the fluid is the line that splits urine from stool.
Before you look at the letters, say the task in plain words. If you cannot say it, you are about to answer a different question from the one on the page.
Five options, each with a job
Options A through E are not filler. One is the best mechanism, structure, or action for this patient. The other four are usually true facts attached to the wrong patient, the wrong time, or the wrong tissue. Penicillinase is a real staphylococcal enzyme, and it explains a penicillin G result, and it does not explain oxacillin resistance. A patent vitelline duct really can wet an umbilicus, and the fluid is intestinal contents, not urine. When you review, write one clause for each letter: what that choice would look like, and which line of this vignette rules it out. “It is wrong” is not a review.
The educational objective is the one sentence you should be able to say the next morning without the vignette in front of you. Every sample below ends with that sentence. If you can only retell the story, you have not finished the item. If you can say the objective, and also say why the nearest distractor failed, you have.
A repeatable way to do one item
- Read the lead-in first. Name the task: mechanism, nerve, structure, next step, or pattern.
- Read the vignette in time order. Note the tempo and the result that does not fit your first idea.
- Cover the explanation and choose a letter. If two letters remain, name the finding that splits them.
- Read the explanation once, slowly. Check the correct letter and every other letter against the stem.
- Close the item and write the educational objective in your own words. Make one flashcard only if that sentence was new.
A card made from a question should hold one fact. “After a brief hypotensive hour, the earliest hepatocyte change is failure of the sodium pump” is a card. The patient’s age and the endoscopy are not. Missed questions come back after 1, 3, 7, and 21 days, which helps only if that first review produced a sentence you can repeat.
How many, and in what order
On StepLobe, a custom block can be timed at about 90 seconds a question, or left in tutor mode so the explanation opens as you answer. An hour is a useful block. The pass guarantee does not count questions past 400 in a single day toward the plan. That ceiling is practical: past it, you are collecting clicks, not objectives. Review the block the same day. A block you cannot review is a block to skip.
Early in a system, use a short tutor set on that system and read every option. When the objectives feel familiar, mix systems and use a clock. Mixed blocks are where second-order questions earn their keep, because the chapter title is no longer sitting in the margin. The USMLE Step 1 practice questions guide is about building those mixed days around a 14-block test day. If you want to try the method on a free set before you buy anything, use the free USMLE-style questions guide and the samples printed there.
What the NBME-style bank includes
The NBME-style bank has 3,494 original Step 1 questions in this format, with lab tables, an exam mode, and explanations. A separate USMLE-style bank currently includes 2,984 original questions, each with an explanation of the correct answer and of every other option. Beside the banks are 33,914 one-fact flashcards in 16 decks, 163 visual study packs, and a day-by-day plan from today to your exam date. The web student panel is live now. Apps for iPhone, iPad, Mac, and Android are still on the way.
A free account needs no card. It includes 10 questions from each bank with full explanations, 50 flashcards, 2 study packs, the first week of a plan, and a 50-question sample exam from either bank. The sample uses a test-day screen and ends in a score report. Those scores are estimates, for practice, not an official result. The free 50-question exam is the fastest way to feel the clock. Full access is listed in the pricing section.
StepLobe is not affiliated with or endorsed by NBME, FSMB, or USMLE. “NBME-style” describes the shape of our questions. These pages are for study only. They are not medical advice.
A week that uses the bank
- Set the exam date and the hours you actually have. The study plan places blocks, cards, and packs on those days.
- On two or three days, do one tutor block in a system you are learning. Review it the same day. One card per new objective.
- On two days, do a mixed timed block. Mark anything you guessed, even if the guess was right.
- Keep one day for review only. No new questions. Redo the marked items and the cards that came due.
- If you are buying a plan the guarantee covers, read the rules on the pass guarantee before you count on it. The guarantee is about following the plan.
Use the four samples below as one sitting of the method. Choose a letter before you read the answer box. Then check every option, not only the correct one. When you want a longer, timed set, go to the free sample exam.
Four free NBME-style questions
These items are original StepLobe questions, printed in full. Nothing is hidden behind a login or a click. Read the vignette in time order, answer the lead-in, then use the explanation, every option, and the educational objective.
Free sample 1 · General Pathology
Original general pathology vignette
A 54-year-old man is brought to the emergency department 45 minutes after he vomited a large amount of bright red blood at home. He has had epigastric pain for 3 weeks and black stools for 2 days. He has no history of liver disease and takes no medications. He does not drink alcohol or use illicit drugs. His temperature is 36.4°C (97.5°F), pulse is 134/min, respirations are 24/min, and blood pressure is 74/42 mm Hg. The skin is cool and clammy. There is tenderness to palpation over the epigastrium. The liver is not enlarged. He receives intravenous crystalloid and 3 units of packed red blood cells. Ninety minutes after arrival, his blood pressure is 114/72 mm Hg. Upper endoscopy shows a bleeding ulcer in the duodenal bulb, and the ulcer is treated endoscopically. Serologic tests for hepatitis A, B, and C viruses are negative. He has an uneventful recovery. Laboratory studies show:
| Test | Day 1 (arrival) | Day 2 | Day 10 |
|---|---|---|---|
| Hemoglobin | 9.1 g/dL | 9.8 g/dL | 11.6 g/dL |
| Prothrombin time | 12 sec | 13 sec | 12 sec |
| Serum bilirubin, total | 0.7 mg/dL | 0.9 mg/dL | 0.6 mg/dL |
| Serum AST | 26 U/L | 310 U/L | 22 U/L |
| Serum ALT | 30 U/L | 265 U/L | 34 U/L |
Which of the following is the most likely mechanism of the earliest hepatocyte injury in this patient during the period of hypotension?
- A.Accumulation of reactive oxygen species during reperfusion
- B.Depletion of glutathione by a reactive drug metabolite
- C.Failure of Na+/K+-ATPase with entry of sodium and water
- D.Influx of calcium with activation of membrane phospholipases
- E.Release of cytochrome c from damaged mitochondria
Correct answer: C
During hypotension, hepatic hypoxia halts oxidative phosphorylation. Without ATP, the Na+/K+-ATPase fails, so Na+ accumulates in the cell, water follows osmotically, and hepatocytes swell. This is the earliest and a reversible form of hypoxic injury.
Oxygen is the final electron acceptor of the electron transport chain. In shock, zone 3 hepatocytes, which receive the least-oxygenated blood, lose ATP production first. When the Na+/K+-ATPase fails, Na+ accumulates inside the cell and K+ leaks out, and water follows osmotically. The cell swells, the endoplasmic reticulum dilates, and the membrane forms blebs. At the same time, anaerobic glycolysis depletes glycogen and lowers intracellular pH, and ribosomes detach from the ER. If perfusion returns before mitochondria and membranes are severely damaged, ATP is regenerated, the pump restores ion gradients, and the cell recovers. This patient's aminotransferases returned to normal and his PT and bilirubin stayed normal, consistent with that recovery.
Why each option is right or wrong
- A. Reactive oxygen species form when oxygen returns to ischemic tissue, after the hypotension ends. This is reperfusion injury, not the first change during hypoperfusion.
- B. Glutathione depletion requires a reactive metabolite such as NAPQI. He takes no medications, and the timing follows shock, not a drug ingestion.
- C. Correct. Hypoxia lowers ATP, and the Na+/K+-ATPase fails. Intracellular Na+ and water then cause swelling, the earliest change, and it reverses when perfusion is restored.
- D. Phospholipase activation by massive Ca2+ influx destroys membranes. It marks a later, irreversible stage of injury, not the earliest change.
- E. Cytochrome c release triggers intrinsic apoptosis through caspase-9. It is not the initial event of brief hypoxia, which starts with ATP-driven ion-pump failure.
Educational objective. In brief hypoxic injury, ATP depletion stops the Na+/K+-ATPase, so Na+ and water enter the cell and cause reversible cellular swelling.
Free sample 2 · Microbiology
Original microbiology vignette
A 16-year-old boy comes to the office because of a 4-day history of a painful, enlarging lump on his right forearm. He is on his high school wrestling team, and two teammates have had similar lesions this season. He is otherwise healthy and takes no medications. His temperature is 37.6°C (99.7°F), pulse is 82/min, respirations are 14/min, and blood pressure is 118/72 mm Hg. Physical examination shows a 3-cm, warm, tender, fluctuant nodule with a central pustule and surrounding erythema on the dorsal right forearm. There is no lymphangitic streaking. The lesion is incised and drained. Gram stain of the purulent material shows gram-positive cocci in clusters. Culture grows colonies that are catalase-positive and coagulase-positive. Antimicrobial susceptibility testing shows:
| Antimicrobial | Result |
|---|---|
| Cefazolin | Resistant |
| Clindamycin | Susceptible |
| Oxacillin | Resistant |
| Penicillin G | Resistant |
| Trimethoprim-sulfamethoxazole | Susceptible |
| Vancomycin | Susceptible |
Which of the following is the most likely mechanism of this organism's resistance to oxacillin?
- A.Decreased drug entry through outer membrane porin channels
- B.Enzymatic hydrolysis of the β-lactam ring by penicillinase
- C.Increased drug export by a membrane efflux pump
- D.Production of a penicillin-binding protein with low affinity for β-lactams
- E.Substitution of D-alanyl-D-lactate in peptidoglycan precursors
Correct answer: D
Oxacillin-resistant Staphylococcus aureus carries mecA, which encodes PBP2a. This transpeptidase binds β-lactams poorly, so cell-wall cross-linking continues even when the drug is present.
β-lactams mimic the D-Ala-D-Ala end of peptidoglycan precursors and acylate the active-site serine of penicillin-binding proteins, which blocks transpeptidase cross-linking. MRSA acquires the mobile element SCCmec, which carries mecA. mecA encodes PBP2a, whose active site is poorly accessible and acylates very slowly. PBP2a therefore keeps cross-linking the cell wall after the native PBPs are inhibited. Because the drug target itself has changed, this boy's isolate resists oxacillin and cefazolin even though both drugs withstand penicillinase, and adding a β-lactamase inhibitor would not help. Anti-MRSA cephalosporins such as ceftaroline were designed to bind PBP2a. Non-β-lactam drugs such as vancomycin and trimethoprim-sulfamethoxazole remain active.
Why each option is right or wrong
- A. Gram-positive bacteria have no outer membrane, so porin channels cannot limit drug entry in S. aureus.
- B. Staphylococcal penicillinase explains the penicillin G resistance. Oxacillin's bulky side chain shields its β-lactam ring, and cefazolin also resists this enzyme.
- C. S. aureus does not resist β-lactams by efflux. Their PBP targets lie on the outer surface of the cell membrane, so pumping drug from the cytoplasm would not help.
- D. Correct. mecA-encoded PBP2a binds β-lactams poorly and keeps cross-linking peptidoglycan. This explains resistance to both oxacillin and cefazolin.
- E. The vanA D-Ala-D-Lac change blocks vancomycin binding, but this isolate is vancomycin-susceptible.
Educational objective. Oxacillin resistance in S. aureus results from mecA-encoded PBP2a, a penicillin-binding protein with low β-lactam affinity.
Free sample 3 · Endocrine
Original endocrine vignette
A 29-year-old woman comes to the office because of a 4-month history of palpitations, heat intolerance, and a 6-kg (13-lb) weight loss despite an increased appetite. For 2 months, both eyes have felt gritty, and she has had double vision when looking upward. The double vision does not vary during the day. She has smoked one-half pack of cigarettes daily for 10 years. She takes no medications. Her temperature is 37.4°C (99.3°F), pulse is 112/min, respirations are 16/min, and blood pressure is 138/64 mm Hg. Physical examination shows warm, moist skin and a fine tremor of the outstretched hands. The thyroid gland is diffusely enlarged and nontender, and a bruit is heard over both lobes. Both globes protrude, and the upper eyelids are retracted so that sclera is visible above each iris. The periorbital tissues are swollen, and the conjunctivae are injected. Upward gaze is limited in both eyes. Laboratory studies show:
| Test | Value |
|---|---|
| TSH | 0.02 μU/mL |
| Thyroxine (T4) | 21 μg/dL |
| Triiodothyronine (T3) | 340 ng/dL |
MRI of the orbits shows bilateral enlargement of the extraocular muscle bellies with sparing of the tendons. The volume of retro-orbital fat is increased.
Which of the following is the most likely mechanism of the protrusion of this patient's eyes?
- A.Antibody blockade of acetylcholine receptors at extraocular neuromuscular junctions
- B.Antibody stimulation of orbital fibroblasts, increasing glycosaminoglycan synthesis and adipocyte differentiation
- C.Catecholamine-enhanced contraction of the superior tarsal muscles, retracting the upper eyelids
- D.Deposition of circulating antigen-antibody complexes in the walls of orbital blood vessels
- E.Increased orbital venous pressure from a carotid artery-cavernous sinus fistula
Correct answer: B
TSH-receptor-stimulating IgG and orbital T cells activate orbital fibroblasts and preadipocytes. These cells make water-binding glycosaminoglycans and new fat. The added soft-tissue volume inside the rigid bony orbit pushes the globes forward.
In Graves disease, IgG against the TSH receptor acts as an agonist. On thyroid follicular cells it drives hormone synthesis and hyperplasia. Orbital fibroblasts also express the TSH receptor, together with the IGF-1 receptor. Antibody binding plus cytokines from infiltrating T cells activates these fibroblasts to secrete hyaluronan. Hyaluronan binds water and swells the interstitium between extraocular muscle fibers, which is why the bellies enlarge while the tendons are spared. A subset of fibroblasts (preadipocytes) differentiates into adipocytes and expands the retro-orbital fat. The bony orbit cannot expand, so the added volume pushes the globes forward. Later fibrosis stiffens the muscles. A stiff inferior rectus restricts upgaze, as in this patient.
Why each option is right or wrong
- A. Acetylcholine-receptor antibodies cause fatigable ptosis and diplopia, not proptosis. This patient's diplopia is constant, and her muscle bellies are enlarged.
- B. Correct. TSH-receptor antibodies activate orbital fibroblasts. The resulting glycosaminoglycan accumulation and adipogenesis expand the orbital contents, matching the MRI findings.
- C. Sympathetic tone in the Müller muscle explains the lid retraction. It cannot push the globe forward or enlarge muscles and fat.
- D. Graves orbitopathy is driven by a stimulating antibody and T cells (type II, receptor-activating). It is not an immune-complex vasculitis.
- E. A fistula causes unilateral, pulsatile proptosis, typically after trauma, with a dilated superior ophthalmic vein. This patient's disease is bilateral and accompanies hyperthyroidism.
Educational objective. In Graves orbitopathy, TSH-receptor antibodies activate orbital fibroblasts and preadipocytes, causing glycosaminoglycan accumulation and adipogenesis that expand orbital volume and produce proptosis.
Free sample 4 · Renal
Original renal vignette
A 1-month-old boy is brought to the office because of a 2-week history of a persistently wet umbilicus. His umbilical cord stump separated at 14 days of age. Since then, his mother has noticed clear, pale yellow fluid draining from the umbilicus several times daily, with more fluid when he cries. He wets six to eight diapers daily and has normal stools. He was born at term after an uncomplicated pregnancy. He is breastfed and has had no fever or vomiting. He is at the 50th percentile for length and weight. His temperature is 37.0°C (98.6°F), pulse is 144/min, and respirations are 38/min. Physical examination shows a moist umbilicus with a small central opening. There is no periumbilical erythema or induration and no polypoid tissue. When he cries, clear fluid flows from the opening. Abdominal examination shows no masses. The genitalia are normal, and both testes are descended. Analysis of the umbilical fluid shows urea nitrogen and creatinine concentrations many times higher than those in his serum. No bile or fecal material is present.
Persistence of which of the following embryologic structures is the most likely cause of this patient's findings?
- A.Allantois
- B.Cloaca
- C.Mesonephric duct
- D.Urogenital sinus
- E.Vitelline duct
Correct answer: A
Allantois. Its intraembryonic part, the urachus, normally fibroses into the median umbilical ligament. If it stays patent, the bladder dome drains urine through the umbilicus, and the flow increases when crying raises intra-abdominal pressure.
The allantois begins as a diverticulum from the caudal yolk sac and hindgut and extends into the connecting stalk. Its intraembryonic segment joins the apex of the developing bladder, which forms from the urogenital sinus. That segment, the urachus, normally narrows to a fibrous cord, the median umbilical ligament, by around birth. If the entire lumen persists, urine passes from the bladder to the umbilicus, especially when crying or straining raises bladder pressure, as in this infant. Partial persistence instead produces a urachal sinus at the umbilicus, a urachal cyst in the middle, or a vesicourachal diverticulum at the bladder dome. Urachal remnants also explain adenocarcinoma at the bladder dome in adults.
Why each option is right or wrong
- A. Correct. The urachus is the allantoic remnant connecting the bladder dome to the umbilicus. If it stays patent, urine drains from the umbilicus and the flow increases when he cries.
- B. The urorectal septum divides the cloaca into the urogenital sinus and the anorectal canal. Cloacal defects affect the perineum, not the umbilicus, and his genitalia and stools are normal.
- C. The mesonephric duct gives rise to the ureteric bud and male genital ducts. It does not connect the bladder to the umbilicus.
- D. The urogenital sinus normally persists as most of the bladder and the urethra. The abnormal channel here is the allantoic extension above the bladder dome.
- E. A patent vitelline duct also drains through the umbilicus, but it discharges meconium or stool from the ileum. This fluid is urine without bile.
Educational objective. Urine draining from an infant's umbilicus reflects a patent urachus from failed obliteration of the allantois.
For study only. Not medical advice. StepLobe is not affiliated with or endorsed by NBME, FSMB or USMLE.
What to take from these four
The liver item is about time: several real injuries happen later than the first hour of low perfusion. The oxacillin item is about which result the mechanism has to explain. The eye item separates orbital expansion from lid retraction. The infant item is decided by what the fluid is. If you wrote four objectives in your own words, you used the page the way a block should be used. The question guide hub links this method to the Step 1 day and to the free set.
The sample exam needs a free account and no card. Founding price is $14.99/month or $139/year ($11.58/month). Yearly starts with 3 days free, card required.
Keep going
- USMLE Step 1 practice questionsHow to place mixed blocks on a 14-block test day, and how cards and questions share one objective.
- Free USMLE-style questionsWhat a useful free set includes, and how to spend a 50-question sample without wasting it.
- All question guidesA short map of the banks, the samples, and which page to read first.
- Free 50-question examNBME-style or USMLE-style, on a test-day screen, with a score report. No card.
- Study planExam date and daily hours in. A day-by-day plan out.
- Mnemonics book2nd edition: 717 mnemonics, 161 real photos, 169 diagrams and 136 questions. Buy now.
- PricingFounding monthly and yearly prices, and what the full banks include.
Questions students ask
What does NBME-style mean on StepLobe?
It describes the format of original StepLobe questions: a chronological vignette, no buzzword shortcut, five options, and a lead-in that asks for a mechanism, structure, or next step rather than a nickname. StepLobe is not affiliated with or endorsed by NBME, FSMB, or USMLE.
How is an NBME-style question structured?
The stem runs in time order: who the patient is, what happened, what the exam and labs show, and what changed later. The lead-in states the task. One of the five options is best. The other four are usually true ideas that belong to a different patient, time, or tissue. A finished review includes the correct explanation, a reason for each distractor, and one educational objective.
How many NBME-style questions does StepLobe have?
The NBME-style bank has 3,494 original questions. A separate USMLE-style bank currently includes 2,984 original questions. There are also 33,914 flashcards. A free account can try 10 questions from each bank and a 50-question sample exam, with no card.
Are these official NBME or USMLE questions?
No. They are original StepLobe items written for study. They are not retired exam forms, and they are not endorsed by the NBME, the FSMB, or the USMLE program.
How should I review a question I missed?
State the task the lead-in actually asked. Then write why the correct option fits this timeline, and one clause for each other option saying which line of the stem rules it out. Turn the educational objective into a single flashcard if the fact was new. StepLobe brings missed questions back after 1, 3, 7, and 21 days.
StepLobe is not affiliated with or endorsed by NBME, FSMB or USMLE. “NBME-style” and “USMLE-style” describe the format of original StepLobe questions. For study only. Not medical advice.