1
NBME 30
NBME 30 FINAL EXAM QUESTIONS &
ANSWERS |GRADE A|100% CORRECT (NEW
2025/2026) (VERIFIED SOLUTIONS)
Exam Section 1: Item 1 of 50
National Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
1. A 33-year-old woman comes to the physician because of a 3-day history of nausea and
light-headedness. Her last menstrual period was 5 weeks ago. She is apprehensive. Physical
examination shows no abnormalities. Her serum B-human chorionic
gonadotropin concentration is increased. At this stage in the pregnancy, progesterone is most
likely produced within which of the following structures?
A) Corpus albicans
B) Corpus luteum
C) Pituitary gland
D) Placental cytotrophoblast
E) Placental syncytiotrophoblast - ANS ✓B.
Pregnancy is suspected when there is a missed or delayed menstrual period. During a normal
menstrual period, follicle-stimulating hormone and luteinizing hormone (FSH and LH,
respectively) concentrations increase and stimulate the developing follicle. The
follicle produces estrogen, which leads to proliferation of the endometrium in preparation for
implantation of a fertilized ovum. As estrogen rises, a surge occurs, which in turn stimulates a
surge in LH that causes ovulation. Immediately following ovulation, the corpus
luteum forms. The corpus luteum secretes progesterone to maintain the endometrial lining. If
no implantation occurs, the corpus luteum degrades to the corpus albicans and estrogen and
progesterone concentrations decrease, causing menstruation. However,
during pregnancy, the placenta develops from embryo implantation. The placenta then begins
to secrete human chorionic gonadotropin, which acts to maintain the corpus luteum and its
secretion of progesterone, which is necessary for maintenance of the
pregnancy. As the placenta develops, it becomes primarily responsible for progesterone
production around seven to ten weeks of gestation. As this patient is at five weeks of
gestation, her progesterone production is still primarily performed by the corpus luteum.
Incorrect Answers: A, C, D, andE.
The corpus albicans (Choice A) is the degraded corpus luteum that develops because of the
absence of embryo implantation. It does not secrete hormones.
The pituitary gland (Choice C) is responsible for secreting FSH and LH, as well as prolactin
and thyroid-stimulating hormone. While FSH and LH play a role in the development of an
ovarian follicle, the pituitary gland does not directly produce progesterone.
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Placental cytotrophoblast (Choice D) is the inner layer of the chorion and is vital for the
implantation of a
2. A study is done to determine the relationship between use of oral contraceptives and
cervical cancer. Study subjects include 50,000 women who are using oral contraceptives and
50,000 women who have had a tubal ligation. After 2 years of follow-up, the
rate of in situ cervical cancer is 18 per 10,000 in the oral contraceptive group and 3 per
10,000 (p < 0.05) in the tubal ligation group. Which of the following is the estimated relative
risk of cervical cancer among women who have had a tubal ligation compared
with women who use oral contraceptives?
A) 3 - 50,000 = 0.00006
B) 3 18 = 0.17
C) 18 - 3 = 6
D) 18 - 3 +10 = 17.7
E) 18 - 3 = 15
F) 18 + 3 = 21
G) Indeterminable from the data given - ANS ✓B.
Relative risk (RR) describes the difference in likelihood of the occurrence of a particular
disease outcome between two groups of patients with or without a particular exposure. In this
case, the outcome of cervical cancer in situ is compared between two exposures,
the use of oral contraceptives or the use of tubal ligation for contraception. Calculations of
relative risk are commonly performed in cohort studies. RR is calculated by dividing the
fraction of patients with a positive exposure and who developed disease (a) amongst
all patients who were exposed which includes those exposed who did not develop disease (b),
(a + b), by the fraction of patients with a negative exposure and who developed disease (c)
amongst all patients who were not exposed which includes those who did not
develop disease (d), (c + d). RR thus equals (a / (a + b) / (c/ (c + d)). RR values greater than
1.0 indicate an increased risk for developing disease in association with the exposure,
whereas values less than 1.0 indicate a reduced risk for developing disease, and
RR equal to 1.0 indicates that the disease outcome and the exposure are not related. In this
case, RR of cervical cancer in situ among women who have had a tubal ligation compared
with women who use oral contraceptives is calculated as (3/ 10,000) -
(18/10,000) = 3 18 = 0.17.
%3D
Incorrect Answers: A, C, D, E, F, and G.
3 - 50,000 = 0.00006 (Choice A) is an incorrect computation of the total fraction of women
with a tubal ligation who developed cervical cancer in situ, as the data are presented per
10,000 patients. Therefore, if the fraction of women with a tubal ligation who
developed cervical cancer in situ were to be calculated, it would be 3/10,000 persons or
15/50,000 in absolute numbers.
18 3 = 6 (Choice C) computes the RR of developing of cervical cancer in situ among wo
3. A study is conducted to assess the accuracy of a new rapid test to detect a virulent bacterial
infection. This infection has an 80% mortality rate if it is not identified early in its course;
however, prompt administration of antibiotics decreases the mortality rate to
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less than 5%. The risks of this antibiotic therapy are minimal. A total of 10,000 participants
are enrolled and undergo assessment with the new test. The graph shows the distribution of
infected and noninfected participants according to the results of the test.
Which of the following labeled points is most appropriate for use as the optimal diagnostic
cut point for results of this test?
Not
Infected
infected
ABCDE
A)
B)
C)
D)
E) - ANS ✓B.
The cut point of the test should be set such that all persons with the infection result as
positive so that there are few false negatives. The threshold should be set to maximize
sensitivity, which equals the true positive test results divided by the sum of true positive
and false negative test results. Therefore, as sensitivity approaches 1.0, all patients who have
the disease will be detected by the test (there will be no false negatives). In this example, high
sensitivity is critical, as the disease has an 80% mortality rate if not
detected and treated early. Therefore, a priority should be placed on sensitivity when deciding
the cut point threshold for positive and negative results. Specificity is calculated by the true
negative test results divided by the sum of true negative and false positive
results. Increasing sensitivity comes at the expense of specificity; by setting the cut point to
include all persons with the disease, many false positives will be introduced as persons
without the disease have results above the cut point. Patients testing negative on
a sensitive test can be safely considered disease free, whereas patients who test positive
should receive additional diagnostic evaluation or treatment. In this example, a bimodal
distribution of patients with and without disease is presented. All patients without
disease are included in the area beneath the not-infected curve, while all patients with disease
are included in the area beneath the infected curve. There is overlap between the two,
suggesting that some patients will test equivalently on the test but may or may
not have the disease. Setting the cut point to point B would permit all patients within the area
under the infected curve to be identified as positive, which maximizes sensitivity, while
minimizing the number of false positives, and there
4. A 66-year-old man with type 2 diabetes mellitus and hypertension is brought to the
emergency department 30 minutes after the sudden onset of left eyelid drooping, double
vision, and mild weakness of the right hand and leg. His pulse is 88/min and regular,
and blood pressure is 159/99 mm Hg. Examination of the head shows a substantially droopy
left eyelid, and in primary gaze, the left eye is exotropic and somewhat lower than the right.
He has slowed finger movements on the right, a pronator drift with the
right hand, and mild hyperreflexia on the right. Which of the following is the most likely site
and diagnosis of the patient's lesion?
A) Angular gyrus (Gerstmann syndrome)
B) Dorsolateral thalamus (Dejerine-Roussy syndrome)
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C) Lower medulla (Wallenberg syndrome)
D) Lower midbrain (Weber syndrome)
E) U - ANS ✓D.
This patient likely has a lesion of the lower midbrain that affects the cerebral peduncle and
the oculomotor nerve, which causes contralateral hemiparesis and ipsilateral oculomotor
palsy, known as Weber syndrome. The cerebral peduncle refers to the anterior
portion of the midbrain and includes the crus cerebri, which contains the corticospinal tract
and is supplied by paramedian branches of the posterior cerebral artery. Upper motor neurons
of the corticospinal tract originate in the primary motor cortex, descend
ipsilaterally through the internal capsule and midbrain (within the crus cerebri), decussate in
the caudal medulla, and then descend contralaterally in the spinal cord to synapse with the
contralateral lower motor neuron. A brainstem lesion of the corticospinal tract
leads to contralateral weakness in an upper motor neuron pattern of dysfunction (eg, spastic
paralysis, pronator drift, and hyperreflexia). The oculomotor nerve (cranial nerve III) is
located anteriorly between the two cerebral peduncles and may also be affected by
strokes of the paramedian branches of the posterior cerebral artery, leading to ipsilateral
dysfunction of the extraocular muscles and consequent diplopia along with ptosis and a
deficit in pupillary constriction. CVAS occur because of ischemic or hemorrhagic loss of
blood supply to the brain. Approximately 80-85% of CVAS are ischemic, commonly arising
from thromboembolic disease (eg, middle cerebral artery occlusion from a thrombus),
whereas 15-20% of CVAS are hemorrhagic and caused by blood vessel rupture (eg,
hypertension-related intraparenchymal hemorrhage from a perforating artery). Risk factors
for CVAS include smoking, hypertension, diabetes mellitus, carotid or intracranial
atherosclerotic disease, history of hypercoagulability, atrial fibrillation, and advanced age.
Classic
5. A 12-year-old boy is brought to the physician by his parents because of bed-wetting. He
urinates 10 to 15 times each day. He says that he is constantly thirsty and drinks large
quantities of liquid throughout the day. Urinalysis shows a specific gravity of
1.003. A 24-hour urine collection shows a creatinine clearance of 140 mL/min, with a total
urine volume of 7600 mL and urine osmolality of 230 mOsmol/kg H,O. A tumor affecting
which of the following hypothalamic nuclei is most likely involved in producing
this patient's symptoms?
A) Anterior
B) Arcuate
C) Dorsomedial
D) Lateral
E) Posterior
F) Supraoptic
G) Ventromedial - ANS ✓F.
Central diabetes insipidus may result from a tumor involving the hypothalamic
paraventricular and supraoptic nuclei and is characterized by the inadequate secretion of
antidiuretic hormone (ADH, also known as vasopressin) from the posterior pituitary.
Normally,
NBME 30
NBME 30
NBME 30 FINAL EXAM QUESTIONS &
ANSWERS |GRADE A|100% CORRECT (NEW
2025/2026) (VERIFIED SOLUTIONS)
Exam Section 1: Item 1 of 50
National Board of Medical Examiners®
Comprehensive Basic Science Self-Assessment
1. A 33-year-old woman comes to the physician because of a 3-day history of nausea and
light-headedness. Her last menstrual period was 5 weeks ago. She is apprehensive. Physical
examination shows no abnormalities. Her serum B-human chorionic
gonadotropin concentration is increased. At this stage in the pregnancy, progesterone is most
likely produced within which of the following structures?
A) Corpus albicans
B) Corpus luteum
C) Pituitary gland
D) Placental cytotrophoblast
E) Placental syncytiotrophoblast - ANS ✓B.
Pregnancy is suspected when there is a missed or delayed menstrual period. During a normal
menstrual period, follicle-stimulating hormone and luteinizing hormone (FSH and LH,
respectively) concentrations increase and stimulate the developing follicle. The
follicle produces estrogen, which leads to proliferation of the endometrium in preparation for
implantation of a fertilized ovum. As estrogen rises, a surge occurs, which in turn stimulates a
surge in LH that causes ovulation. Immediately following ovulation, the corpus
luteum forms. The corpus luteum secretes progesterone to maintain the endometrial lining. If
no implantation occurs, the corpus luteum degrades to the corpus albicans and estrogen and
progesterone concentrations decrease, causing menstruation. However,
during pregnancy, the placenta develops from embryo implantation. The placenta then begins
to secrete human chorionic gonadotropin, which acts to maintain the corpus luteum and its
secretion of progesterone, which is necessary for maintenance of the
pregnancy. As the placenta develops, it becomes primarily responsible for progesterone
production around seven to ten weeks of gestation. As this patient is at five weeks of
gestation, her progesterone production is still primarily performed by the corpus luteum.
Incorrect Answers: A, C, D, andE.
The corpus albicans (Choice A) is the degraded corpus luteum that develops because of the
absence of embryo implantation. It does not secrete hormones.
The pituitary gland (Choice C) is responsible for secreting FSH and LH, as well as prolactin
and thyroid-stimulating hormone. While FSH and LH play a role in the development of an
ovarian follicle, the pituitary gland does not directly produce progesterone.
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Placental cytotrophoblast (Choice D) is the inner layer of the chorion and is vital for the
implantation of a
2. A study is done to determine the relationship between use of oral contraceptives and
cervical cancer. Study subjects include 50,000 women who are using oral contraceptives and
50,000 women who have had a tubal ligation. After 2 years of follow-up, the
rate of in situ cervical cancer is 18 per 10,000 in the oral contraceptive group and 3 per
10,000 (p < 0.05) in the tubal ligation group. Which of the following is the estimated relative
risk of cervical cancer among women who have had a tubal ligation compared
with women who use oral contraceptives?
A) 3 - 50,000 = 0.00006
B) 3 18 = 0.17
C) 18 - 3 = 6
D) 18 - 3 +10 = 17.7
E) 18 - 3 = 15
F) 18 + 3 = 21
G) Indeterminable from the data given - ANS ✓B.
Relative risk (RR) describes the difference in likelihood of the occurrence of a particular
disease outcome between two groups of patients with or without a particular exposure. In this
case, the outcome of cervical cancer in situ is compared between two exposures,
the use of oral contraceptives or the use of tubal ligation for contraception. Calculations of
relative risk are commonly performed in cohort studies. RR is calculated by dividing the
fraction of patients with a positive exposure and who developed disease (a) amongst
all patients who were exposed which includes those exposed who did not develop disease (b),
(a + b), by the fraction of patients with a negative exposure and who developed disease (c)
amongst all patients who were not exposed which includes those who did not
develop disease (d), (c + d). RR thus equals (a / (a + b) / (c/ (c + d)). RR values greater than
1.0 indicate an increased risk for developing disease in association with the exposure,
whereas values less than 1.0 indicate a reduced risk for developing disease, and
RR equal to 1.0 indicates that the disease outcome and the exposure are not related. In this
case, RR of cervical cancer in situ among women who have had a tubal ligation compared
with women who use oral contraceptives is calculated as (3/ 10,000) -
(18/10,000) = 3 18 = 0.17.
%3D
Incorrect Answers: A, C, D, E, F, and G.
3 - 50,000 = 0.00006 (Choice A) is an incorrect computation of the total fraction of women
with a tubal ligation who developed cervical cancer in situ, as the data are presented per
10,000 patients. Therefore, if the fraction of women with a tubal ligation who
developed cervical cancer in situ were to be calculated, it would be 3/10,000 persons or
15/50,000 in absolute numbers.
18 3 = 6 (Choice C) computes the RR of developing of cervical cancer in situ among wo
3. A study is conducted to assess the accuracy of a new rapid test to detect a virulent bacterial
infection. This infection has an 80% mortality rate if it is not identified early in its course;
however, prompt administration of antibiotics decreases the mortality rate to
NBME 30
, 3
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less than 5%. The risks of this antibiotic therapy are minimal. A total of 10,000 participants
are enrolled and undergo assessment with the new test. The graph shows the distribution of
infected and noninfected participants according to the results of the test.
Which of the following labeled points is most appropriate for use as the optimal diagnostic
cut point for results of this test?
Not
Infected
infected
ABCDE
A)
B)
C)
D)
E) - ANS ✓B.
The cut point of the test should be set such that all persons with the infection result as
positive so that there are few false negatives. The threshold should be set to maximize
sensitivity, which equals the true positive test results divided by the sum of true positive
and false negative test results. Therefore, as sensitivity approaches 1.0, all patients who have
the disease will be detected by the test (there will be no false negatives). In this example, high
sensitivity is critical, as the disease has an 80% mortality rate if not
detected and treated early. Therefore, a priority should be placed on sensitivity when deciding
the cut point threshold for positive and negative results. Specificity is calculated by the true
negative test results divided by the sum of true negative and false positive
results. Increasing sensitivity comes at the expense of specificity; by setting the cut point to
include all persons with the disease, many false positives will be introduced as persons
without the disease have results above the cut point. Patients testing negative on
a sensitive test can be safely considered disease free, whereas patients who test positive
should receive additional diagnostic evaluation or treatment. In this example, a bimodal
distribution of patients with and without disease is presented. All patients without
disease are included in the area beneath the not-infected curve, while all patients with disease
are included in the area beneath the infected curve. There is overlap between the two,
suggesting that some patients will test equivalently on the test but may or may
not have the disease. Setting the cut point to point B would permit all patients within the area
under the infected curve to be identified as positive, which maximizes sensitivity, while
minimizing the number of false positives, and there
4. A 66-year-old man with type 2 diabetes mellitus and hypertension is brought to the
emergency department 30 minutes after the sudden onset of left eyelid drooping, double
vision, and mild weakness of the right hand and leg. His pulse is 88/min and regular,
and blood pressure is 159/99 mm Hg. Examination of the head shows a substantially droopy
left eyelid, and in primary gaze, the left eye is exotropic and somewhat lower than the right.
He has slowed finger movements on the right, a pronator drift with the
right hand, and mild hyperreflexia on the right. Which of the following is the most likely site
and diagnosis of the patient's lesion?
A) Angular gyrus (Gerstmann syndrome)
B) Dorsolateral thalamus (Dejerine-Roussy syndrome)
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C) Lower medulla (Wallenberg syndrome)
D) Lower midbrain (Weber syndrome)
E) U - ANS ✓D.
This patient likely has a lesion of the lower midbrain that affects the cerebral peduncle and
the oculomotor nerve, which causes contralateral hemiparesis and ipsilateral oculomotor
palsy, known as Weber syndrome. The cerebral peduncle refers to the anterior
portion of the midbrain and includes the crus cerebri, which contains the corticospinal tract
and is supplied by paramedian branches of the posterior cerebral artery. Upper motor neurons
of the corticospinal tract originate in the primary motor cortex, descend
ipsilaterally through the internal capsule and midbrain (within the crus cerebri), decussate in
the caudal medulla, and then descend contralaterally in the spinal cord to synapse with the
contralateral lower motor neuron. A brainstem lesion of the corticospinal tract
leads to contralateral weakness in an upper motor neuron pattern of dysfunction (eg, spastic
paralysis, pronator drift, and hyperreflexia). The oculomotor nerve (cranial nerve III) is
located anteriorly between the two cerebral peduncles and may also be affected by
strokes of the paramedian branches of the posterior cerebral artery, leading to ipsilateral
dysfunction of the extraocular muscles and consequent diplopia along with ptosis and a
deficit in pupillary constriction. CVAS occur because of ischemic or hemorrhagic loss of
blood supply to the brain. Approximately 80-85% of CVAS are ischemic, commonly arising
from thromboembolic disease (eg, middle cerebral artery occlusion from a thrombus),
whereas 15-20% of CVAS are hemorrhagic and caused by blood vessel rupture (eg,
hypertension-related intraparenchymal hemorrhage from a perforating artery). Risk factors
for CVAS include smoking, hypertension, diabetes mellitus, carotid or intracranial
atherosclerotic disease, history of hypercoagulability, atrial fibrillation, and advanced age.
Classic
5. A 12-year-old boy is brought to the physician by his parents because of bed-wetting. He
urinates 10 to 15 times each day. He says that he is constantly thirsty and drinks large
quantities of liquid throughout the day. Urinalysis shows a specific gravity of
1.003. A 24-hour urine collection shows a creatinine clearance of 140 mL/min, with a total
urine volume of 7600 mL and urine osmolality of 230 mOsmol/kg H,O. A tumor affecting
which of the following hypothalamic nuclei is most likely involved in producing
this patient's symptoms?
A) Anterior
B) Arcuate
C) Dorsomedial
D) Lateral
E) Posterior
F) Supraoptic
G) Ventromedial - ANS ✓F.
Central diabetes insipidus may result from a tumor involving the hypothalamic
paraventricular and supraoptic nuclei and is characterized by the inadequate secretion of
antidiuretic hormone (ADH, also known as vasopressin) from the posterior pituitary.
Normally,
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