USMLE Step 1 is the first exam in the United States Medical Licensing Examination sequence. It assesses your understanding of the foundational sciences that underpin the safe and effective practice of medicine, and is reported on a pass/fail basis.
CliniQuiz.AI generates curriculum-aligned Step 1 practice questions that follow the official content outline, so you can drill the topics that actually appear on test day:
Anatomy, physiology, and biochemistry
Pathology, pharmacology, and microbiology
Immunology, genetics, and behavioral sciences
Organ-system integration and clinical correlation
Every question comes with a detailed explanation, and an AI tutor can break down the reasoning, review your mistakes, and target your weak areas. Start with a free sample quiz below—no account required.
Sample Questions
A 42-year-old woman, gravida 2, para 2, presents with 6 months of intermittent vaginal spotting between menstrual periods. Her periods occur every 28–30 days and last 4 days. She has no pelvic pain, postcoital bleeding, or recent changes in weight. She takes no hormonal medications or anticoagulants. Pelvic examination shows a normal cervix and a mobile, normal-sized uterus. A urine pregnancy test is negative, and her hemoglobin concentration is 12.4 g/dL. An office endometrial biopsy shows benign proliferative endometrium. Because the spotting persists, saline infusion sonohysterography is performed and reveals a 1.5-cm smooth, pedunculated lesion projecting into the uterine cavity. Doppler imaging shows a single vessel entering its stalk. The surrounding myometrium appears homogeneous. The lesion is removed hysteroscopically. Which of the following histologic findings is most likely present in the resected tissue?
Benign endometrial glands and stroma embedded within myometrium surrounded by hypertrophied smooth muscle
Interlacing fascicles of uniform smooth muscle cells with elongated nuclei and minimal mitotic activity
Crowded, irregular endometrial glands with an increased gland-to-stroma ratio and cytologically bland epithelium
These are characteristic findings of an endometrial polyp, a localized overgrowth of endometrial glands and stroma around a vascular core. Polyps commonly cause intermenstrual spotting and appear as smooth intracavitary lesions with a single feeding vessel. A blind office biopsy may sample the surrounding normal endometrium and miss the focal lesion, explaining the initially benign biopsy result.
A 27-year-old woman presents with vaginal bleeding lasting 17 days after 4 months without a menstrual period. Similar episodes have occurred twice during the past year. Since late adolescence, her menstrual cycles have occurred at intervals of 45–120 days. She also reports worsening acne and coarse hair growth on her chin. She takes no medications and has no history of easy bruising, epistaxis, or excessive bleeding after dental procedures. Her blood pressure is 112/70 mm Hg, pulse is 86/min, and BMI is 25 kg/m². Pelvic examination reveals a normal-sized, nontender uterus. A urine pregnancy test is negative. Hemoglobin is 9.8 g/dL, mean corpuscular volume is 75 fL, thyroid-stimulating hormone is 1.8 mIU/L, and prolactin is 12 ng/mL. Transvaginal ultrasonography shows a 13-mm endometrium without a focal lesion or myometrial mass. Because of recurrent prolonged bleeding, an endometrial biopsy is obtained. It shows irregularly shaped glands of variable size, numerous mitotic figures, and focal stromal breakdown without glandular crowding or cytologic atypia. Which of the following mechanisms best explains the endometrial findings and bleeding?
Persistent corpus luteum activity with sustained progesterone exposure and maintained secretory differentiation
Reduced ovarian estrogen production with diminished endometrial proliferation and progressive mucosal thinning
Failure of corpus luteum formation with loss of cyclic progesterone exposure
Defective platelet adhesion to vascular collagen with impaired hemostasis during endometrial shedding
Premature corpus luteum regression with early withdrawal of progesterone from secretory endometrium
Show answer and explanation
Answer: Failure of corpus luteum formation with loss of cyclic progesterone exposure
The prolonged, unpredictable cycles and clinical hyperandrogenism suggest chronic anovulation, most likely associated with polycystic ovary syndrome. Without ovulation, a corpus luteum does not form, eliminating the normal cyclic progesterone exposure that converts proliferative endometrium into secretory endometrium. Continued estrogenic stimulation produces disordered glandular proliferation and an unstable endometrial lining that breaks down asynchronously, causing prolonged, irregular bleeding. The biopsy demonstrates this pattern without the glandular crowding characteristic of endometrial hyperplasia.
A 10-year-old boy is evaluated for slowed growth and declining school performance over the past year. His height has increased by 3 cm during that time, while his weight remains at the 50th percentile. He has longstanding food selectivity and eats primarily rice, chicken, potatoes, fruit, and unfortified oat beverages. He does not consume dairy products, eggs, or seafood, and his family uses noniodized sea salt. Examination shows mild, symmetric, nontender thyroid enlargement. Laboratory studies show a TSH concentration of 9.2 mIU/L and a free T4 concentration of 0.7 ng/dL. Thyroid peroxidase antibodies are undetectable. A complete 24-hour urine collection contains 20 µg of iodine. Compared with an age-matched child receiving adequate nutrition, which additional physiologic pattern is most likely before treatment?
The dietary history, low urinary iodine excretion, elevated TSH, and reduced free T4 indicate iodine-deficient hypothyroidism. When iodine is scarce, thyroid hormone production shifts toward T3, which requires three iodine atoms rather than the four required for T4; circulating T3 is therefore relatively preserved, increasing the T3:T4 ratio. Reduced thyroid hormone feedback also increases TSH, which stimulates sodium-iodide symporter activity and raises fractional radioiodide uptake despite limited hormone production.
A 69-year-old man presents with 3 weeks of palpitations, heat intolerance, and a 4-kg (9-lb) weight loss. He lives in a rural community where his diet has consisted primarily of locally grown grains and vegetables, and his household has traditionally used noniodized salt. Eight weeks ago, a community nutrition program began replacing household salt with iodized salt. He has had painless anterior neck enlargement for approximately 25 years. Three months ago, his serum TSH was 1.2 mIU/L. He takes no medications or dietary supplements. His pulse is 118/min and irregular. Examination shows a fine hand tremor and an enlarged, irregular thyroid without tenderness or ophthalmopathy. ECG shows atrial fibrillation. Serum TSH is now <0.01 mIU/L, free T4 is 2.8 ng/dL, and total T3 is 265 ng/dL. TSH-receptor antibodies are negative. Ultrasonography shows multiple bilateral thyroid nodules. Which of the following mechanisms best explains the change in this patient's thyroid function?
Increased hormone synthesis through antibody-mediated stimulation of thyroid receptors
Reduced hormone synthesis through acute inhibition of iodide organification
Increased hormone synthesis by TSH-independent thyroid follicular cells
Release of stored hormone through inflammatory disruption of thyroid follicles
Show answer and explanation
Answer: Increased hormone synthesis by TSH-independent thyroid follicular cells
This patient has iodine-induced hyperthyroidism, or the Jod-Basedow phenomenon, following correction of longstanding iodine deficiency. Chronic iodine deficiency promotes thyroid enlargement and, over time, can lead to multinodular tissue containing functionally autonomous follicular cells. These cells may initially produce limited amounts of hormone because iodine availability is low. Restoring iodine supplies substrate for increased hormone synthesis that is not appropriately restrained by suppression of TSH. His longstanding nodular goiter, recent salt iodization, and newly developed thyrotoxicosis strongly support this mechanism.
A 62-year-old man with rheumatoid arthritis presents with 4 months of worsening fatigue and reduced exercise tolerance. He also reports increasing hand pain and morning stiffness lasting 2 hours. He takes methotrexate, folic acid, and naproxen daily. He denies hematemesis, melena, or hematochezia. Examination shows conjunctival pallor and swelling of several metacarpophalangeal joints. Laboratory studies show:
Hemoglobin: 9.6 g/dL
Mean corpuscular volume: 75 fL
Red cell distribution width: 18.9%
Reticulocyte count: 0.7%
Serum ferritin: 85 ng/mL
C-reactive protein: 42 mg/L
Creatinine: 0.9 mg/dL
Which additional finding would most strongly support depletion of total-body iron stores rather than inflammation-mediated restriction of iron availability alone?
Soluble transferrin receptor is derived largely from receptors on erythroid precursors. Cellular iron deficiency increases receptor expression and the amount of soluble receptor released into the circulation. This measurement is less affected by inflammation than ferritin and can help identify absolute iron deficiency superimposed on anemia of inflammation. Increased erythropoietic activity can also elevate it, but this patient's low reticulocyte count supports a hypoproliferative process. His ferritin concentration does not exclude depleted stores because active inflammation can raise ferritin.
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Frequently Asked Questions
Is USMLE Step 1 still pass/fail?
Yes, for every exam taken since January 26, 2022. The passing standard is equal to 196 on the old three-digit scale, which USMLE says works out to about 60% of questions answered correctly.
How many questions are on Step 1, and how long is the test day?
About 280 questions in a single 8-hour session. Since May 14, 2026 the exam runs as 14 blocks of 30 minutes with up to 20 questions each, plus at least 55 minutes of break time and an optional 5-minute tutorial. Prep materials that describe seven 60-minute blocks are using the old format.
What is the Step 1 pass rate?
In 2025, 93% of first-time takers from US MD schools passed, along with 89% from US DO schools and 75% from schools outside the US. Repeat takers do much worse: 71% for US MD students and 54% for international students.
What does Step 1 cover?
Foundational science applied to clinical problems. Pathology shows up in 45 to 55% of questions and physiology in 30 to 40%, and a single question often tests more than one discipline. By organ system, reproductive and endocrine (12 to 16%) and respiratory and renal (11 to 15%) carry the most weight. Biostatistics, epidemiology, and communication skills add another 10 to 15%, so they deserve real study time.
How much does Step 1 cost?
$695 for exams in 2026 and 2027. Testing outside the US and Canada adds a $210 region fee. US and Canadian students register through NBME, while international students and graduates have registered through FSMB since January 12, 2026. See the full USMLE cost breakdown.
Do I need to pass Step 1 before taking Step 2 CK?
No. You can take them in either order, but you need to pass both before you can sit Step 3.
How many times can I retake Step 1?
You can attempt the same Step at most three times in 12 months. Four attempts at any Step without passing make you ineligible for the whole USMLE, and incomplete attempts count toward that limit. Once you pass, you cannot retake it.
How soon do Step 1 results come out?
Usually within four weeks, though USMLE advises allowing up to eight. Your score report stays available online for about a year.
What is the best way to use practice questions for Step 1?
Do them timed and mixed, and spend more time on the review than on the questions themselves, including the ones you got right. CliniQuiz has more than 2,200 Step 1 questions with an explanation for every answer option, and the AI tutor can unpack any concept you are unsure of. Read how to get the most out of a question bank.