NBME EXAM QUESTION AND
ANSWERS.
Exam Section 1: Item 1 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
1. A75-year-old man has decreased exercise tolerance and occasional syncopal episodes related to
B B B B B B B B B B B B
Bexertion. Left-heart catheterization discloses this pressure tracing (Ao -aorta; LV -left ventricle; LA -
B B B B B B B B B B B B B
left atrium). The most frequently encountered mechanism underlying this disorder is which of the
B B B B B B B B B B B B B
Bfollowing?
ЕCG
A) Amyloid deposition
B B
150-
B) Calcification
B
C) Cystic medial necrosis
B B B
D) Pericardial effusion
B B
100-
O E) Septal hypertrophy
B B B
Ao
50-
LV
LA
Time
Time-
Correct Answer: B. B B
The pressure tracing demonstrates a large pressure gradient between the left ventricle and aorta
B B B B B B B B B B B B B
Bduring systole, which is consistent with the diagnosis of aortic stenosis. In the setting of aortic
B B B B B B B B B B B B B B B
Bstenosis, the left ventricle must generate higher pressures in order to
B B B B B B B B B B
overcome the opening resistance of the stenotic valve. This increased - ANS >>
B B B B B B B B B B B B B
2
Exam Section 1: Item 2 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
2. New reagents are being designed to treat graft-versus-host disease in HLA-unrelated bone marrow
B B B B B B B B B B B B B
Btransplant recipients. Reagents should be designed that selectively deplete which of the following
B B B B B B B B B B B B
Bdonor cells? B
A) B lymphocytes
B B
O B) Dendritic cells
B B B
C) Macrophages
B
D) Neutrophils
B
E) T lymphocytes
B B
Correct Answer: E. B B
,T lymphocytes, which are responsible for the immune attack against the recipient, should be the
B B B B B B B B B B B B B B
Btarget of agents used to treat graft-versus-host disease (GVHD) in HLA-unrelated bone marrow
B B B B B B B B B B B B
Btransplant recipients. Prior to grafting of allogeneic stem cells in a bone
B B B B B B B B B B B
marrow transplant, recipient native marrow must be completely ablated. It is then replaced with
B B B B B B B B B B B B B
Bdonor marrow, which recolonizes the marrow cavity. Successful transplantation results in
B B B B B B B B B B
Breconstitution of the immune system with the donor's i - ANS >> B B B B B B B B B B B B
3
Exam Section 1: Item 3 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
3. A9-year-old boy has had alopecia and hypocalcemia since birth. His serum 1,25-
B B B B B B B B B B B B
dihydroxycholecalciferol concentration is within the reference range, serum 24,25- B B B B B B B B
dihydroxycholecalciferol is undetectable. Serum parathyroid hormone concentration is above B B B B B B B B
the upper limit of the laboratory assay and needs to be reassayed at a dilution. The results are
B B B B B B B B B B B B B B B B B
Bpending. Which of the following is the most likely cause of his condition?
B B B B B B B B B B B B
O A) Loss-of-function mutation in the calcium-sensing receptor
B B B B B B B
B) Multiple endocrine neoplasia type I
B B B B B
C) Mutations inactivating the vitamin D 24-hydroxylase gene
B B B B B B B
D) Mutations inactivating the vitamin D receptor
B B B B B B
Correct Answer: D. B B
Vitamin D plays a role in serum calcium and phosphate homeostasis by promoting the intestinal
B B B B B B B B B B B B B B
Babsorption of calcium and phosphate. Parathyroid hormone (PTH) also h - ANS >>
B B B B B B B B B B B B B
4
Exam Section 1: Item 4 of 50
B B B B B B
National Board of Medical Examiners®B B B B
Comprehensive Basic Science Self-Assessment B B B
4. Assuming the positive predictive value of a test is 50% and the negative predictive value is 75%,
B B B B B B B B B B B B B B B B B
Bwhich of the following tables are consistent with these values?
B B B B B B B B B
Disease
Disease
Present
Absent
Present
Absent
A
B
Positive
50
50
750
250
Test
Negative
250
750
50
50
Positive
,250
750
50
50
Test
Negative
50
50
750
250
E Cannot be determined from data given
B B B B B B
A)
B)
C)
D)
E)
Correct Answer: A. B B
Positive predictive value (PPV) and negative predictive value (NPV) are statistical measurements that
B B B B B B B B B B B B
define the proportion of positive test results that are true positives (positive tests in patients who
B B B B B B B B B B B B B B B B
have the condition) and true negatives (negative tests in
B B B B B B B B B
patients without the condition). PPV is thus defined as (true positives [TP]) / (TP + false positives [FP])
B B B B B B B B B B B B B B B B B
and measures the probability of a patient having the dise - ANS >>
B B B B B B B B B B B B B B
5
Exam Section 1: Item 5 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
5. A 43-year-old woman comes to the physician because of vague discomfort, nausea, easy bruising,
B B B B B B B B B B B B B B
and weight loss. Her prothrombin time is increased. The most likely cause of the increased
B B B B B B B B B B B B B B B
prothrombin time is damage to which of the following cells?
B B B B B B B B B B
A) Endothelial cells
B B
B) Fibroblasts
B
C) Нерatocytes
B
D) Macrophages
B
E) Skeletal muscle cells
B B B
F) T lymphocytes
B B
Correct Answer: C. B B
Hepatocyte injury accounts for this patient's symptoms and coagulation abnormality. Hepatocytes
B B B B B B B B B B
filter and detoxify portal venous blood, metabolize medications, synthesize coagulation factors
B B B B B B B B B B B
(including fibrinogen, prothrombin, factors V, VII, IX, X, XI, XII, proteins
B B B B B B B B B B B
C and S), complement, apoproteins, triglycerides, cholesterol, bile acids, and albumin, and play critical
B B B B B B B B B B B B B
roles in biochemical metabolism (eg, gluconeogenesis). Many manifest - ANS >>
B B B B B B B B B B B B
6
Exam Section 1: Item 6 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
6. A 63-year-old man has had this gradually enlarging lesion on his right forearm for the past 3 years.
B B B B B B B B B B B B B B B B B B
Which of the following is the most likely diagnosis?
B B B B B B B B B
A) Actinic keratosis
B B
, B) Blue nevus
B B
C) Compound nevus
B B
D) Dermatofibroma
B
E) Halo nevus
B B
F) Hemangioma
B
G) Malignant melanoma
B B
H) Pyogenic granuloma
B B
I) Seborrheic keratosis
B B
1 cmB
J) Squamous cell carcinoma
B B B
Correct Answer: G. B B
Malignant melanoma is likely to be present when a lesion demonstrates asymmetry, irregular
B B B B B B B B B B B B
Bappearing borders, variable coloration, a diameter greater than 6 mm, and rapid evolution in
B B B B B B B B B B B B B
Bcharacteristics. Malignant melanoma can rapidly invade and metastasize, B B B B B B B
which carries a poor prognosis when diagnosed late. Subtypes include superficial spreading, nodular,
B B B B B B B B B B B B
Blentigo maligna, and acral lentiginous. Any lesion with features suggestive of malignan - ANS >>
B B B B B B B B B B B B B B B
7
Exam Section 1: Item 7 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
7. A 66-year-old man has a surgical excision of a brain mass; a photomicrograph of excised tissue is
B B B B B B B B B B B B B B B B B
Bshown. He has smoked 1 pack of cigarettes daily for the past 50 years. His blood pressure is 130/90
B B B B B B B B B B B B B B B B B B
Bmm Hg. B
Laboratory studies show polycythemia, hypercalcemia, and microscopic hematuria. Immunostaining of
B B B B B B B B B
Bthe tissue is positive for epithelial membrane antigen and negative for carcinoembryonic antigen.
B B B B B B B B B B B B
BWhich of B
the following is the most likely site of the primary neoplasm?
B B B B B B B B B B
O A) Colon
B B
B) Kidney
B
C) LiverB
D) Lung B
E) Lymph node
B B
O F) Prostate
B B
G) Testis
B
Correct Answer: B. B B
Renal cell carcinoma (RCC) is an adenocarcinoma of tubular epithelial cells. RCC is the most common
B B B B B B B B B B B B B B B
Bprimary malignancy of the kidney and most commonly occurs in older, male smokers. It can present
B B B B B B B B B B B B B B B
Bwith gross or microscopic hematuria, flank pain, we - ANS >>
B B B B B B B B B B B
8
Exam Section 1: Item 8 of 50
B B B B B B
Național Board of Medical Examiners® B B B B
Comprehensive Basic Science Self-Assessment B B B
8. In a study designed to test the effectiveness of a new drug in the treatment of endometriosis, 100
B B B B B B B B B B B B B B B B B B
Bwomen are randomly assigned to one of two groups: 48 of the women receive the new drug and 52
B B B B B B B B B B B B B B B B B B
Breceive standard therapy. Which of the following is the
B B B B B B B B
major benefit of assigning patients in this manner?
B B B B B B B
O A) The effect of confounding variables is decreased
B B B B B B B B
B) The likelihood of achieving statistical significance is increased
B B B B B B B B
ANSWERS.
Exam Section 1: Item 1 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
1. A75-year-old man has decreased exercise tolerance and occasional syncopal episodes related to
B B B B B B B B B B B B
Bexertion. Left-heart catheterization discloses this pressure tracing (Ao -aorta; LV -left ventricle; LA -
B B B B B B B B B B B B B
left atrium). The most frequently encountered mechanism underlying this disorder is which of the
B B B B B B B B B B B B B
Bfollowing?
ЕCG
A) Amyloid deposition
B B
150-
B) Calcification
B
C) Cystic medial necrosis
B B B
D) Pericardial effusion
B B
100-
O E) Septal hypertrophy
B B B
Ao
50-
LV
LA
Time
Time-
Correct Answer: B. B B
The pressure tracing demonstrates a large pressure gradient between the left ventricle and aorta
B B B B B B B B B B B B B
Bduring systole, which is consistent with the diagnosis of aortic stenosis. In the setting of aortic
B B B B B B B B B B B B B B B
Bstenosis, the left ventricle must generate higher pressures in order to
B B B B B B B B B B
overcome the opening resistance of the stenotic valve. This increased - ANS >>
B B B B B B B B B B B B B
2
Exam Section 1: Item 2 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
2. New reagents are being designed to treat graft-versus-host disease in HLA-unrelated bone marrow
B B B B B B B B B B B B B
Btransplant recipients. Reagents should be designed that selectively deplete which of the following
B B B B B B B B B B B B
Bdonor cells? B
A) B lymphocytes
B B
O B) Dendritic cells
B B B
C) Macrophages
B
D) Neutrophils
B
E) T lymphocytes
B B
Correct Answer: E. B B
,T lymphocytes, which are responsible for the immune attack against the recipient, should be the
B B B B B B B B B B B B B B
Btarget of agents used to treat graft-versus-host disease (GVHD) in HLA-unrelated bone marrow
B B B B B B B B B B B B
Btransplant recipients. Prior to grafting of allogeneic stem cells in a bone
B B B B B B B B B B B
marrow transplant, recipient native marrow must be completely ablated. It is then replaced with
B B B B B B B B B B B B B
Bdonor marrow, which recolonizes the marrow cavity. Successful transplantation results in
B B B B B B B B B B
Breconstitution of the immune system with the donor's i - ANS >> B B B B B B B B B B B B
3
Exam Section 1: Item 3 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
3. A9-year-old boy has had alopecia and hypocalcemia since birth. His serum 1,25-
B B B B B B B B B B B B
dihydroxycholecalciferol concentration is within the reference range, serum 24,25- B B B B B B B B
dihydroxycholecalciferol is undetectable. Serum parathyroid hormone concentration is above B B B B B B B B
the upper limit of the laboratory assay and needs to be reassayed at a dilution. The results are
B B B B B B B B B B B B B B B B B
Bpending. Which of the following is the most likely cause of his condition?
B B B B B B B B B B B B
O A) Loss-of-function mutation in the calcium-sensing receptor
B B B B B B B
B) Multiple endocrine neoplasia type I
B B B B B
C) Mutations inactivating the vitamin D 24-hydroxylase gene
B B B B B B B
D) Mutations inactivating the vitamin D receptor
B B B B B B
Correct Answer: D. B B
Vitamin D plays a role in serum calcium and phosphate homeostasis by promoting the intestinal
B B B B B B B B B B B B B B
Babsorption of calcium and phosphate. Parathyroid hormone (PTH) also h - ANS >>
B B B B B B B B B B B B B
4
Exam Section 1: Item 4 of 50
B B B B B B
National Board of Medical Examiners®B B B B
Comprehensive Basic Science Self-Assessment B B B
4. Assuming the positive predictive value of a test is 50% and the negative predictive value is 75%,
B B B B B B B B B B B B B B B B B
Bwhich of the following tables are consistent with these values?
B B B B B B B B B
Disease
Disease
Present
Absent
Present
Absent
A
B
Positive
50
50
750
250
Test
Negative
250
750
50
50
Positive
,250
750
50
50
Test
Negative
50
50
750
250
E Cannot be determined from data given
B B B B B B
A)
B)
C)
D)
E)
Correct Answer: A. B B
Positive predictive value (PPV) and negative predictive value (NPV) are statistical measurements that
B B B B B B B B B B B B
define the proportion of positive test results that are true positives (positive tests in patients who
B B B B B B B B B B B B B B B B
have the condition) and true negatives (negative tests in
B B B B B B B B B
patients without the condition). PPV is thus defined as (true positives [TP]) / (TP + false positives [FP])
B B B B B B B B B B B B B B B B B
and measures the probability of a patient having the dise - ANS >>
B B B B B B B B B B B B B B
5
Exam Section 1: Item 5 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
5. A 43-year-old woman comes to the physician because of vague discomfort, nausea, easy bruising,
B B B B B B B B B B B B B B
and weight loss. Her prothrombin time is increased. The most likely cause of the increased
B B B B B B B B B B B B B B B
prothrombin time is damage to which of the following cells?
B B B B B B B B B B
A) Endothelial cells
B B
B) Fibroblasts
B
C) Нерatocytes
B
D) Macrophages
B
E) Skeletal muscle cells
B B B
F) T lymphocytes
B B
Correct Answer: C. B B
Hepatocyte injury accounts for this patient's symptoms and coagulation abnormality. Hepatocytes
B B B B B B B B B B
filter and detoxify portal venous blood, metabolize medications, synthesize coagulation factors
B B B B B B B B B B B
(including fibrinogen, prothrombin, factors V, VII, IX, X, XI, XII, proteins
B B B B B B B B B B B
C and S), complement, apoproteins, triglycerides, cholesterol, bile acids, and albumin, and play critical
B B B B B B B B B B B B B
roles in biochemical metabolism (eg, gluconeogenesis). Many manifest - ANS >>
B B B B B B B B B B B B
6
Exam Section 1: Item 6 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
6. A 63-year-old man has had this gradually enlarging lesion on his right forearm for the past 3 years.
B B B B B B B B B B B B B B B B B B
Which of the following is the most likely diagnosis?
B B B B B B B B B
A) Actinic keratosis
B B
, B) Blue nevus
B B
C) Compound nevus
B B
D) Dermatofibroma
B
E) Halo nevus
B B
F) Hemangioma
B
G) Malignant melanoma
B B
H) Pyogenic granuloma
B B
I) Seborrheic keratosis
B B
1 cmB
J) Squamous cell carcinoma
B B B
Correct Answer: G. B B
Malignant melanoma is likely to be present when a lesion demonstrates asymmetry, irregular
B B B B B B B B B B B B
Bappearing borders, variable coloration, a diameter greater than 6 mm, and rapid evolution in
B B B B B B B B B B B B B
Bcharacteristics. Malignant melanoma can rapidly invade and metastasize, B B B B B B B
which carries a poor prognosis when diagnosed late. Subtypes include superficial spreading, nodular,
B B B B B B B B B B B B
Blentigo maligna, and acral lentiginous. Any lesion with features suggestive of malignan - ANS >>
B B B B B B B B B B B B B B B
7
Exam Section 1: Item 7 of 50
B B B B B B
National Board of Medical Examiners B B B B
Comprehensive Basic Science Self-Assessment B B B
7. A 66-year-old man has a surgical excision of a brain mass; a photomicrograph of excised tissue is
B B B B B B B B B B B B B B B B B
Bshown. He has smoked 1 pack of cigarettes daily for the past 50 years. His blood pressure is 130/90
B B B B B B B B B B B B B B B B B B
Bmm Hg. B
Laboratory studies show polycythemia, hypercalcemia, and microscopic hematuria. Immunostaining of
B B B B B B B B B
Bthe tissue is positive for epithelial membrane antigen and negative for carcinoembryonic antigen.
B B B B B B B B B B B B
BWhich of B
the following is the most likely site of the primary neoplasm?
B B B B B B B B B B
O A) Colon
B B
B) Kidney
B
C) LiverB
D) Lung B
E) Lymph node
B B
O F) Prostate
B B
G) Testis
B
Correct Answer: B. B B
Renal cell carcinoma (RCC) is an adenocarcinoma of tubular epithelial cells. RCC is the most common
B B B B B B B B B B B B B B B
Bprimary malignancy of the kidney and most commonly occurs in older, male smokers. It can present
B B B B B B B B B B B B B B B
Bwith gross or microscopic hematuria, flank pain, we - ANS >>
B B B B B B B B B B B
8
Exam Section 1: Item 8 of 50
B B B B B B
Național Board of Medical Examiners® B B B B
Comprehensive Basic Science Self-Assessment B B B
8. In a study designed to test the effectiveness of a new drug in the treatment of endometriosis, 100
B B B B B B B B B B B B B B B B B B
Bwomen are randomly assigned to one of two groups: 48 of the women receive the new drug and 52
B B B B B B B B B B B B B B B B B B
Breceive standard therapy. Which of the following is the
B B B B B B B B
major benefit of assigning patients in this manner?
B B B B B B B
O A) The effect of confounding variables is decreased
B B B B B B B B
B) The likelihood of achieving statistical significance is increased
B B B B B B B B
