COMSAE Phase 1 Form 115 Practice Exam
Questions And Well Graded Solutions With
Rationales Updated 2026-2027
Master your COMLEX Level 1 diagnostic prep with this comprehensive
study guide for the COMSAE Phase 1 Form 115 exam. This document
provides clear practice questions alongside bolded correct answers and
detailed, italicized rationales covering core medical sciences, high-yield
organ systems, and OMM/OPP concepts. Perfect for tracking diagnostic
milestones, evaluating board readiness, and identifying weak areas. Score
higher, study smarter, and pass your osteopathic boards with confidence!
Question 1
A 64-year-old male presents to the emergency department with severe, crushing
chest pain that radiates to his left arm. An electrocardiogram (ECG) reveals ST-
segment elevations in leads II, III, and aVF. Which of the following coronary arteries
is most likely occluded?
A) Left anterior descending artery
B) Left circumflex artery
C) Right coronary artery
D) Left main coronary artery
Rationale: ST-segment elevations in leads II, III, and aVF indicate an acute inferior
wall myocardial infarction. The right coronary artery (RCA) supplies the inferior wall
of the ventricles in the majority of patients (right-dominant circulation). Occlusion of
the left anterior descending artery would present with changes in the anterior leads
(V1-V4), while the left circumflex artery affects the lateral leads (I, aVL, V5-V6).
Question 2
A 22-year-old female presents to her gynecologist with abdominal bloating and pelvic
pain. An ultrasound reveals a large, unilocular ovarian cyst filled with clear fluid. A
biopsy of the tissue confirms a benign epithelial tumor lined with ciliated columnar
epithelium. Which of the following is the most likely diagnosis?
A) Serous cystadenoma
B) Mucinous cystadenoma
C) Brenner tumor
D) Granulosa cell tumor
,Rationale: Serous cystadenomas are the most common benign epithelial ovarian
tumors and are typically filled with clear, serous fluid and lined with ciliated columnar
epithelium. Mucinous cystadenomas are lined by mucus-secreting cells and filled
with thick mucin. Brenner tumors contain bladder-like epithelium (transitional cells).
Granulosa cell tumors are sex cord-stromal tumors that secrete estrogen and feature
Call-Exner bodies.
Question 3
A 45-year-old female presents with progressive fatigue, generalized weakness, and
a distinct darkening of her skin, particularly around her palmar creases and gums.
Laboratory analysis reveals a serum sodium level of 128 mEq/L (normal: 135-145
mEq/L) and a serum potassium level of 5.6 mEq/L (normal: 3.5-5.0 mEq/L). Primary
adrenal insufficiency is suspected. Which of the following hormones is primarily
deficient in this patient causing the electrolyte abnormalities?
A) Cortisol
B) Aldosterone
C) Epinephrine
D) ACTH
Rationale: Primary adrenal insufficiency (Addison's disease) involves the destruction
of all layers of the adrenal cortex. While a deficiency in cortisol causes fatigue and
upregulates ACTH (leading to hyperpigmentation), the severe hyponatremia and
hyperkalemia are directly caused by a lack of aldosterone. Aldosterone normally
promotes sodium reabsorption and potassium excretion in the renal collecting ducts.
Question 1
A 28-year-old female presents with irregular menses, hirsutism, and acne.
Ultrasound reveals multiple small follicles along the periphery of both ovaries,
resembling a "string of pearls." This patient is at an increased risk for developing
which of the following malignancies?
A) Cervical carcinoma
B) Endometrial carcinoma
C) Granulosa cell tumor
D) Serous cystadenocarcinoma
,Rationale: The clinical presentation is highly indicative of Polycystic Ovary Syndrome
(PCOS). In PCOS, chronic anovulation leads to unopposed estrogen exposure
because there is no corpus luteum formed to produce progesterone. This chronic,
unopposed estrogen stimulation causes endometrial hyperplasia, significantly
increasing the long-term risk of endometrial adenocarcinoma.
Question 2
A 42-year-old male is brought to the emergency department after a motorcycle
accident. Physical examination reveals a dropped right foot and an inability to evert
the foot. Sensation is decreased over the dorsum of the right foot. Which nerve was
most likely injured?
A) Deep fibular nerve
B) Tibial nerve
C) Superficial fibular nerve
D) Common fibular nerve
Rationale: The common fibular (peroneal) nerve winds around the neck of the fibula,
making it highly susceptible to trauma. Injury results in "foot drop" due to loss of
dorsiflexion (deep fibular branch) and loss of eversion (superficial fibular branch),
alongside sensory loss over the dorsum of the foot.
Question 3
A 35-year-old male complains of severe, episodic heartburn that worsens after large
meals and when lying flat. An upper endoscopy reveals orange, gastric-like mucosa
extending proximally into the distal esophagus. Biopsy confirms specialized intestinal
metaplasia. This histological change is characterized by the presence of which cell
type?
A) Goblet cells
B) Parietal cells
C) Chief cells
D) Paneth cells
, Rationale: Barrett's esophagus is a complication of chronic GERD characterized by
intestinal metaplasia, where the normal stratified squamous epithelium of the lower
esophagus transforms into simple columnar epithelium. The hallmark histological
finding that confirms intestinal metaplasia is the presence of mucin-producing goblet
cells.
Question 4
A 19-year-old college student presents with a high fever, severe headache, and neck
stiffness. Physical examination reveals a petechial rash on his lower extremities. A
lumbar puncture is performed. Gram stain of the cerebrospinal fluid reveals Gram-
negative diplococci. Which of the following is the most appropriate initial empiric
pharmacotherapy?
A) Vancomycin
B) Ceftriaxone
C) Ampicillin
D) Gentamicin
Rationale: The presentation of fever, altered mental status, nuchal rigidity, a
petechial rash, and Gram-negative diplococci is diagnostic for Neisseria meningitidis
meningitis. Third-generation cephalosporins like ceftriaxone penetrate the blood-
brain barrier effectively and serve as the first-line treatment.
Question 5
A 55-year-old female with a history of rheumatoid arthritis presents with abdominal
pain. She has been taking high-dose naproxen daily for the past six months.
Laboratory findings reveal a microcytic, hypochromic anemia. Which of the following
mechanisms is responsible for her primary gastrointestinal pathology?
A) Direct chemical toxicity to the gastric epithelium
B) Stimulation of histamine H2 receptors
C) Inhibition of cyclooxygenase-1 (COX-1)
D) Upregulation of mucosal prostaglandin production
Questions And Well Graded Solutions With
Rationales Updated 2026-2027
Master your COMLEX Level 1 diagnostic prep with this comprehensive
study guide for the COMSAE Phase 1 Form 115 exam. This document
provides clear practice questions alongside bolded correct answers and
detailed, italicized rationales covering core medical sciences, high-yield
organ systems, and OMM/OPP concepts. Perfect for tracking diagnostic
milestones, evaluating board readiness, and identifying weak areas. Score
higher, study smarter, and pass your osteopathic boards with confidence!
Question 1
A 64-year-old male presents to the emergency department with severe, crushing
chest pain that radiates to his left arm. An electrocardiogram (ECG) reveals ST-
segment elevations in leads II, III, and aVF. Which of the following coronary arteries
is most likely occluded?
A) Left anterior descending artery
B) Left circumflex artery
C) Right coronary artery
D) Left main coronary artery
Rationale: ST-segment elevations in leads II, III, and aVF indicate an acute inferior
wall myocardial infarction. The right coronary artery (RCA) supplies the inferior wall
of the ventricles in the majority of patients (right-dominant circulation). Occlusion of
the left anterior descending artery would present with changes in the anterior leads
(V1-V4), while the left circumflex artery affects the lateral leads (I, aVL, V5-V6).
Question 2
A 22-year-old female presents to her gynecologist with abdominal bloating and pelvic
pain. An ultrasound reveals a large, unilocular ovarian cyst filled with clear fluid. A
biopsy of the tissue confirms a benign epithelial tumor lined with ciliated columnar
epithelium. Which of the following is the most likely diagnosis?
A) Serous cystadenoma
B) Mucinous cystadenoma
C) Brenner tumor
D) Granulosa cell tumor
,Rationale: Serous cystadenomas are the most common benign epithelial ovarian
tumors and are typically filled with clear, serous fluid and lined with ciliated columnar
epithelium. Mucinous cystadenomas are lined by mucus-secreting cells and filled
with thick mucin. Brenner tumors contain bladder-like epithelium (transitional cells).
Granulosa cell tumors are sex cord-stromal tumors that secrete estrogen and feature
Call-Exner bodies.
Question 3
A 45-year-old female presents with progressive fatigue, generalized weakness, and
a distinct darkening of her skin, particularly around her palmar creases and gums.
Laboratory analysis reveals a serum sodium level of 128 mEq/L (normal: 135-145
mEq/L) and a serum potassium level of 5.6 mEq/L (normal: 3.5-5.0 mEq/L). Primary
adrenal insufficiency is suspected. Which of the following hormones is primarily
deficient in this patient causing the electrolyte abnormalities?
A) Cortisol
B) Aldosterone
C) Epinephrine
D) ACTH
Rationale: Primary adrenal insufficiency (Addison's disease) involves the destruction
of all layers of the adrenal cortex. While a deficiency in cortisol causes fatigue and
upregulates ACTH (leading to hyperpigmentation), the severe hyponatremia and
hyperkalemia are directly caused by a lack of aldosterone. Aldosterone normally
promotes sodium reabsorption and potassium excretion in the renal collecting ducts.
Question 1
A 28-year-old female presents with irregular menses, hirsutism, and acne.
Ultrasound reveals multiple small follicles along the periphery of both ovaries,
resembling a "string of pearls." This patient is at an increased risk for developing
which of the following malignancies?
A) Cervical carcinoma
B) Endometrial carcinoma
C) Granulosa cell tumor
D) Serous cystadenocarcinoma
,Rationale: The clinical presentation is highly indicative of Polycystic Ovary Syndrome
(PCOS). In PCOS, chronic anovulation leads to unopposed estrogen exposure
because there is no corpus luteum formed to produce progesterone. This chronic,
unopposed estrogen stimulation causes endometrial hyperplasia, significantly
increasing the long-term risk of endometrial adenocarcinoma.
Question 2
A 42-year-old male is brought to the emergency department after a motorcycle
accident. Physical examination reveals a dropped right foot and an inability to evert
the foot. Sensation is decreased over the dorsum of the right foot. Which nerve was
most likely injured?
A) Deep fibular nerve
B) Tibial nerve
C) Superficial fibular nerve
D) Common fibular nerve
Rationale: The common fibular (peroneal) nerve winds around the neck of the fibula,
making it highly susceptible to trauma. Injury results in "foot drop" due to loss of
dorsiflexion (deep fibular branch) and loss of eversion (superficial fibular branch),
alongside sensory loss over the dorsum of the foot.
Question 3
A 35-year-old male complains of severe, episodic heartburn that worsens after large
meals and when lying flat. An upper endoscopy reveals orange, gastric-like mucosa
extending proximally into the distal esophagus. Biopsy confirms specialized intestinal
metaplasia. This histological change is characterized by the presence of which cell
type?
A) Goblet cells
B) Parietal cells
C) Chief cells
D) Paneth cells
, Rationale: Barrett's esophagus is a complication of chronic GERD characterized by
intestinal metaplasia, where the normal stratified squamous epithelium of the lower
esophagus transforms into simple columnar epithelium. The hallmark histological
finding that confirms intestinal metaplasia is the presence of mucin-producing goblet
cells.
Question 4
A 19-year-old college student presents with a high fever, severe headache, and neck
stiffness. Physical examination reveals a petechial rash on his lower extremities. A
lumbar puncture is performed. Gram stain of the cerebrospinal fluid reveals Gram-
negative diplococci. Which of the following is the most appropriate initial empiric
pharmacotherapy?
A) Vancomycin
B) Ceftriaxone
C) Ampicillin
D) Gentamicin
Rationale: The presentation of fever, altered mental status, nuchal rigidity, a
petechial rash, and Gram-negative diplococci is diagnostic for Neisseria meningitidis
meningitis. Third-generation cephalosporins like ceftriaxone penetrate the blood-
brain barrier effectively and serve as the first-line treatment.
Question 5
A 55-year-old female with a history of rheumatoid arthritis presents with abdominal
pain. She has been taking high-dose naproxen daily for the past six months.
Laboratory findings reveal a microcytic, hypochromic anemia. Which of the following
mechanisms is responsible for her primary gastrointestinal pathology?
A) Direct chemical toxicity to the gastric epithelium
B) Stimulation of histamine H2 receptors
C) Inhibition of cyclooxygenase-1 (COX-1)
D) Upregulation of mucosal prostaglandin production
