NBME 25 ACTUAL EXAMINATION 2025/2026 QUESTIONS
WITH ANSWERS GRADED A+
✔✔5
Exam Section 1: Item 5 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
5. A 43-year-old woman comes to the physician because of vague discomfort, nausea,
easy bruising, and weight loss. Her prothrombin time is increased. The most likely
cause of the increased prothrombin time is damage to which of the following cells?
A) Endothelial cells
B) Fibroblasts
C) Нерatocytes
D) Macrophages
E) Skeletal muscle cells
F) T lymphocytes
Correct Answer: C.
Hepatocyte injury accounts for this patient's symptoms and coagulation abnormality.
Hepatocytes filter and detoxify portal venous blood, metabolize medications, synthesize
coagulation factors (including fibrinogen, prothrombin, factors V, VII, IX, X, XI, XII,
proteins
C and S), complement, apoproteins, triglycerides, cholesterol, bile acids, and albumin,
and play critical roles in biochemical metabolism (eg, gluconeogenesis). Many manifest
- ✔✔
✔✔6
Exam Section 1: Item 6 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
6. A 63-year-old man has had this gradually enlarging lesion on his right forearm for the
past 3 years. Which of the following is the most likely diagnosis?
A) Actinic keratosis
B) Blue nevus
C) Compound nevus
D) Dermatofibroma
E) Halo nevus
F) Hemangioma
G) Malignant melanoma
H) Pyogenic granuloma
I) Seborrheic keratosis
1 cm
J) Squamous cell carcinoma
Correct Answer: G.
Malignant melanoma is likely to be present when a lesion demonstrates asymmetry,
irregular appearing borders, variable coloration, a diameter greater than 6 mm, and
,rapid evolution in characteristics. Malignant melanoma can rapidly invade and
metastasize,
which carries a poor prognosis when diagnosed late. Subtypes include superficial
spreading, nodular, lentigo maligna, and acral lentiginous. Any lesion with features
suggestive of malignan - ✔✔
✔✔7
Exam Section 1: Item 7 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
7. A 66-year-old man has a surgical excision of a brain mass; a photomicrograph of
excised tissue is shown. He has smoked 1 pack of cigarettes daily for the past 50 years.
His blood pressure is 130/90 mm Hg.
Laboratory studies show polycythemia, hypercalcemia, and microscopic hematuria.
Immunostaining of the tissue is positive for epithelial membrane antigen and negative
for carcinoembryonic antigen. Which of
the following is the most likely site of the primary neoplasm?
O A) Colon
B) Kidney
C) Liver
D) Lung
E) Lymph node
O F) Prostate
G) Testis
Correct Answer: B.
Renal cell carcinoma (RCC) is an adenocarcinoma of tubular epithelial cells. RCC is the
most common primary malignancy of the kidney and most commonly occurs in older,
male smokers. It can present with gross or microscopic hematuria, flank pain, we - ✔✔
✔✔8
Exam Section 1: Item 8 of 50
Național Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
8. In a study designed to test the effectiveness of a new drug in the treatment of
endometriosis, 100 women are randomly assigned to one of two groups: 48 of the
women receive the new drug and 52 receive standard therapy. Which of the following is
the
major benefit of assigning patients in this manner?
O A) The effect of confounding variables is decreased
B) The likelihood of achieving statistical significance is increased
C) The power of the study is increased
D) The study groups are equalized
Correct Answer: A.
When conducting a study, there are many potential biases that could impact the results
and lead the investigators to erroneously reject the null hypothesis. One such bias is
confounding bias, in which an unmeasured characteristic differs between two groups of
,subjects and causes a difference in out - ✔✔
✔✔9
Exam Section 1: Item 9 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
9. A 17-year-old girl who is a gymnast is brought to the emergency department 30
minutes after fainting during a competition. Her mother says that the patient eats so little
food that her teeth are decaying and that she has stopped menstruating. She is 165 cm
(5 ft 5 in) tall and weighs 37 kg (82 lb); BMI is 14 kg/m2. Sexual development is Tanner
stage 2. Her pulse is 130/min and blood pressure is 80/50 mm Hg. Physical
examination shows pale, cool skin. There are scars across her knuckles that she says
are cat
scratches. Serum studies show a potassium concentration of 2.9 mEq/L and a chloride
concentration of 92 mEq/L. Which of the following is the most likely diagnosis?
A) Anorexia nervosa (binge eating/purging type)
B) Anorexia nervosa (restricting type)
C) Bulimia nervosa (nonpurging type)
D) Chronically - ✔✔
✔✔10
Exam Section 1: Item 10 of 50
Național Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
10. A fetus exposed to an infection at 22 weeks' gestation appears normal at birth but
later develops a persistent mucopurulent nasal discharge, malformed teeth, skin cracks
and fissures around oral, anal, and vulvar orifices, splenomegaly, and
lymphadenopathy. Which of the following best explains these findings?
A) Inability of maternal rubella antibodies to cross the placental barrier
O B) Increased amounts of herpes simplex virus in amniotic fluid
O C) Maternal failure to generate antibodies to cytomegalovirus
D) Maternally transferred spirochetes replicating in fetal tissue
E) Persistence of HIV in placental tissue
Correct Answer: D.
Congenital syphilis is caused by the maternal transfer of Treponema pallidum
spirochetes through the placenta in the second and third trimesters, which then replicate
in - ✔✔
✔✔11
Exam Section 1: Item 11 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
11. The biological effects of thyroid hormone and retinoic acid are mediated through
similar mechanisms. Which of the following properties is common to the receptors for
these two compounds?
A) Ability to activate phospholipase C
, B) DNA-binding domain
C) Formation of a dimer on binding of hormone
D) Interaction with a G protein
E) Tyrosine kinase activity
Correct Answer: B.
The receptors for retinoic acid and thyroid hormone are both nuclear receptors that
contain DNA-binding domains. Nuclear receptors can initially be located in either the
cytosol or nucleus. They bind to hormones which are either lipophilic and therefore
capable of
diffusion across the outer cell membrane, or which are transported into the cell via
carrier-mediated transport. Once nuclear receptors bind their respective hormones, they
tr - ✔✔
✔✔12
Exam Section 1: Item 12 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
12. A 57-year-old man comes to the physician because of an intermittent cough and a
9-kg (20-lb) weight loss over the past 6 months. He has smoked 1 pack of cigarettes
daily for 42 years. His serum calcium concentration is 13.3 mg/dL. An x-ray of the chest
shows a 4-cm central mass in the left lung. Which of the following is the most likely
diagnosis?
A) Adenocarcinoma of the lung
B) Large cell lymphoma
C) Metastatic osteosarcoma
D) Metastatic renal cell carcinoma
E) Small cell carcinoma of the lung
F) Squamous cell carcinoma of the lung
Correct Answer: F.
Squamous cell carcinoma of the lung is the second most common type of primary lung
cancer after adenocarcinoma. Risk factors for all major types of lung cancer include
tobacco use, secondhand smoke, asbestos, or radon exposure, and a family history of
lu - ✔✔
✔✔13
Exam Section 1: Item 13 of 50
Național Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
13. A 45-year-old woman has had progressive fatigue and mild shortness of breath with
exertion during the past 3 months. She thinks she had rheumatic fever at the age of 10
years. A grade 2/6, rumbling, diastolic murmur is heard at the fifth left intercostal
space in the midclavicular line. A lateral x-ray of the chest shows mild posterior
displacement of the esophagus. Which of the following cardiovascular structures is most
likely responsible for the esophageal displacement?
O A) Descending aorta
B) Left atrium
WITH ANSWERS GRADED A+
✔✔5
Exam Section 1: Item 5 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
5. A 43-year-old woman comes to the physician because of vague discomfort, nausea,
easy bruising, and weight loss. Her prothrombin time is increased. The most likely
cause of the increased prothrombin time is damage to which of the following cells?
A) Endothelial cells
B) Fibroblasts
C) Нерatocytes
D) Macrophages
E) Skeletal muscle cells
F) T lymphocytes
Correct Answer: C.
Hepatocyte injury accounts for this patient's symptoms and coagulation abnormality.
Hepatocytes filter and detoxify portal venous blood, metabolize medications, synthesize
coagulation factors (including fibrinogen, prothrombin, factors V, VII, IX, X, XI, XII,
proteins
C and S), complement, apoproteins, triglycerides, cholesterol, bile acids, and albumin,
and play critical roles in biochemical metabolism (eg, gluconeogenesis). Many manifest
- ✔✔
✔✔6
Exam Section 1: Item 6 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
6. A 63-year-old man has had this gradually enlarging lesion on his right forearm for the
past 3 years. Which of the following is the most likely diagnosis?
A) Actinic keratosis
B) Blue nevus
C) Compound nevus
D) Dermatofibroma
E) Halo nevus
F) Hemangioma
G) Malignant melanoma
H) Pyogenic granuloma
I) Seborrheic keratosis
1 cm
J) Squamous cell carcinoma
Correct Answer: G.
Malignant melanoma is likely to be present when a lesion demonstrates asymmetry,
irregular appearing borders, variable coloration, a diameter greater than 6 mm, and
,rapid evolution in characteristics. Malignant melanoma can rapidly invade and
metastasize,
which carries a poor prognosis when diagnosed late. Subtypes include superficial
spreading, nodular, lentigo maligna, and acral lentiginous. Any lesion with features
suggestive of malignan - ✔✔
✔✔7
Exam Section 1: Item 7 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
7. A 66-year-old man has a surgical excision of a brain mass; a photomicrograph of
excised tissue is shown. He has smoked 1 pack of cigarettes daily for the past 50 years.
His blood pressure is 130/90 mm Hg.
Laboratory studies show polycythemia, hypercalcemia, and microscopic hematuria.
Immunostaining of the tissue is positive for epithelial membrane antigen and negative
for carcinoembryonic antigen. Which of
the following is the most likely site of the primary neoplasm?
O A) Colon
B) Kidney
C) Liver
D) Lung
E) Lymph node
O F) Prostate
G) Testis
Correct Answer: B.
Renal cell carcinoma (RCC) is an adenocarcinoma of tubular epithelial cells. RCC is the
most common primary malignancy of the kidney and most commonly occurs in older,
male smokers. It can present with gross or microscopic hematuria, flank pain, we - ✔✔
✔✔8
Exam Section 1: Item 8 of 50
Național Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
8. In a study designed to test the effectiveness of a new drug in the treatment of
endometriosis, 100 women are randomly assigned to one of two groups: 48 of the
women receive the new drug and 52 receive standard therapy. Which of the following is
the
major benefit of assigning patients in this manner?
O A) The effect of confounding variables is decreased
B) The likelihood of achieving statistical significance is increased
C) The power of the study is increased
D) The study groups are equalized
Correct Answer: A.
When conducting a study, there are many potential biases that could impact the results
and lead the investigators to erroneously reject the null hypothesis. One such bias is
confounding bias, in which an unmeasured characteristic differs between two groups of
,subjects and causes a difference in out - ✔✔
✔✔9
Exam Section 1: Item 9 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
9. A 17-year-old girl who is a gymnast is brought to the emergency department 30
minutes after fainting during a competition. Her mother says that the patient eats so little
food that her teeth are decaying and that she has stopped menstruating. She is 165 cm
(5 ft 5 in) tall and weighs 37 kg (82 lb); BMI is 14 kg/m2. Sexual development is Tanner
stage 2. Her pulse is 130/min and blood pressure is 80/50 mm Hg. Physical
examination shows pale, cool skin. There are scars across her knuckles that she says
are cat
scratches. Serum studies show a potassium concentration of 2.9 mEq/L and a chloride
concentration of 92 mEq/L. Which of the following is the most likely diagnosis?
A) Anorexia nervosa (binge eating/purging type)
B) Anorexia nervosa (restricting type)
C) Bulimia nervosa (nonpurging type)
D) Chronically - ✔✔
✔✔10
Exam Section 1: Item 10 of 50
Național Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
10. A fetus exposed to an infection at 22 weeks' gestation appears normal at birth but
later develops a persistent mucopurulent nasal discharge, malformed teeth, skin cracks
and fissures around oral, anal, and vulvar orifices, splenomegaly, and
lymphadenopathy. Which of the following best explains these findings?
A) Inability of maternal rubella antibodies to cross the placental barrier
O B) Increased amounts of herpes simplex virus in amniotic fluid
O C) Maternal failure to generate antibodies to cytomegalovirus
D) Maternally transferred spirochetes replicating in fetal tissue
E) Persistence of HIV in placental tissue
Correct Answer: D.
Congenital syphilis is caused by the maternal transfer of Treponema pallidum
spirochetes through the placenta in the second and third trimesters, which then replicate
in - ✔✔
✔✔11
Exam Section 1: Item 11 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
11. The biological effects of thyroid hormone and retinoic acid are mediated through
similar mechanisms. Which of the following properties is common to the receptors for
these two compounds?
A) Ability to activate phospholipase C
, B) DNA-binding domain
C) Formation of a dimer on binding of hormone
D) Interaction with a G protein
E) Tyrosine kinase activity
Correct Answer: B.
The receptors for retinoic acid and thyroid hormone are both nuclear receptors that
contain DNA-binding domains. Nuclear receptors can initially be located in either the
cytosol or nucleus. They bind to hormones which are either lipophilic and therefore
capable of
diffusion across the outer cell membrane, or which are transported into the cell via
carrier-mediated transport. Once nuclear receptors bind their respective hormones, they
tr - ✔✔
✔✔12
Exam Section 1: Item 12 of 50
National Board of Medical Examiners
Comprehensive Basic Science Self-Assessment
12. A 57-year-old man comes to the physician because of an intermittent cough and a
9-kg (20-lb) weight loss over the past 6 months. He has smoked 1 pack of cigarettes
daily for 42 years. His serum calcium concentration is 13.3 mg/dL. An x-ray of the chest
shows a 4-cm central mass in the left lung. Which of the following is the most likely
diagnosis?
A) Adenocarcinoma of the lung
B) Large cell lymphoma
C) Metastatic osteosarcoma
D) Metastatic renal cell carcinoma
E) Small cell carcinoma of the lung
F) Squamous cell carcinoma of the lung
Correct Answer: F.
Squamous cell carcinoma of the lung is the second most common type of primary lung
cancer after adenocarcinoma. Risk factors for all major types of lung cancer include
tobacco use, secondhand smoke, asbestos, or radon exposure, and a family history of
lu - ✔✔
✔✔13
Exam Section 1: Item 13 of 50
Național Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
13. A 45-year-old woman has had progressive fatigue and mild shortness of breath with
exertion during the past 3 months. She thinks she had rheumatic fever at the age of 10
years. A grade 2/6, rumbling, diastolic murmur is heard at the fifth left intercostal
space in the midclavicular line. A lateral x-ray of the chest shows mild posterior
displacement of the esophagus. Which of the following cardiovascular structures is most
likely responsible for the esophageal displacement?
O A) Descending aorta
B) Left atrium
