NR 576 FINAL EXAM – DIFFERENTIAL DIAGNOSIS IN
ADULT-GERONTOLOGY PRIMARY CARE 100
COMPREHENSIVE QUESTIONS & CORRECT ANSWERS
LATEST STUDY GUIDE (2026) CHAMBERLAIN
1. Which term describes the ability of a test to correctly identify individuals
who have the disease?
A) Sensitivity
B) Specificity
C) Positive predictive value
D) Negative predictive value
Correct Answer: A) Sensitivity
Rationale: Sensitivity is the proportion of people with a disease who test
positive. A highly sensitive test produces few false negatives and is useful
for ruling out disease. Specificity identifies people without disease.
Predictive values depend on prevalence.
2. A test has high specificity. What does this indicate?
A) It correctly identifies most individuals with disease
B) It correctly identifies most individuals without disease
C) It has few false negatives
D) It is not affected by prevalence
Correct Answer: B) It correctly identifies most individuals without disease
Rationale: Specificity is the ability of a test to correctly identify those
without the disease, producing few false positives. High specificity is useful
for
,confirming a diagnosis after a positive screen. It is not equivalent to
sensitivity or unaffected by prevalence.
3. A negative result on a highly sensitive test is most useful for which purpose?
A) Confirming disease
B) Measuring prevalence
C) Ruling out disease
D) Predicting prognosis
Correct Answer: C) Ruling out disease
Rationale: A highly sensitive test has few false negatives, so a negative
result makes disease unlikely. This helps rule out a condition.
Confirmation is better with a highly specific test. Prevalence and
prognosis are not the primary uses.
4. Positive predictive value increases when which factor increases?
A) Specificity only
B) Sensitivity only
C) Test cost
D) Disease prevalence
Correct Answer: D) Disease prevalence
Rationale: Positive predictive value depends on sensitivity, specificity,
and disease prevalence. As prevalence increases, the proportion of
positive tests
,that are true positives rises. Cost does not affect predictive value.
Sensitivity and specificity also influence but prevalence is a key
determinant.
5. A complete blood count shows MCV 105 fL. This is classified as:
A) Macrocytic anemia
B) Microcytic anemia
C) Normocytic anemia
D) Thrombocytosis
Correct Answer: A) Macrocytic anemia
Rationale: Mean corpuscular volume above 100 fL indicates macrocytic
anemia. Common causes include vitamin B12 and folate deficiency.
Microcytic anemia has MCV below 80 fL, and normocytic anemia has MCV
80 to 100 fL. Thrombocytosis is an elevated platelet count.
6. A 72-year-old patient with fatigue has MCV 108 fL, low serum
B12, and positive anti-intrinsic factor antibodies. What is the likely
diagnosis?
A) Folate deficiency
B) Pernicious anemia
C) Iron deficiency anemia
D) Anemia of chronic disease
Correct Answer: B) Pernicious anemia
, Rationale: Pernicious anemia is caused by vitamin B12 deficiency due to
lack of intrinsic factor. Positive anti-intrinsic factor antibodies are highly
specific. The macrocytic anemia and low B12 support this diagnosis rather
than folate, iron, or chronic disease.
7. Which test best distinguishes vitamin B12 deficiency from folate deficiency?
A) Homocysteine
B) Ferritin
C) Methylmalonic acid
D) Reticulocyte count
Correct Answer: C) Methylmalonic acid
Rationale: Both B12 and folate deficiency elevate homocysteine, but only
B12 deficiency elevates methylmalonic acid. Therefore methylmalonic acid
best distinguishes the two. Ferritin evaluates iron status, and reticulocyte
count reflects red cell production.
8. A patient has microcytic anemia with low ferritin and high TIBC.
Which diagnosis is most likely?
A) Anemia of chronic disease
B) Thalassemia trait
C) Sideroblastic anemia
D) Iron deficiency anemia
Correct Answer: D) Iron deficiency anemia
ADULT-GERONTOLOGY PRIMARY CARE 100
COMPREHENSIVE QUESTIONS & CORRECT ANSWERS
LATEST STUDY GUIDE (2026) CHAMBERLAIN
1. Which term describes the ability of a test to correctly identify individuals
who have the disease?
A) Sensitivity
B) Specificity
C) Positive predictive value
D) Negative predictive value
Correct Answer: A) Sensitivity
Rationale: Sensitivity is the proportion of people with a disease who test
positive. A highly sensitive test produces few false negatives and is useful
for ruling out disease. Specificity identifies people without disease.
Predictive values depend on prevalence.
2. A test has high specificity. What does this indicate?
A) It correctly identifies most individuals with disease
B) It correctly identifies most individuals without disease
C) It has few false negatives
D) It is not affected by prevalence
Correct Answer: B) It correctly identifies most individuals without disease
Rationale: Specificity is the ability of a test to correctly identify those
without the disease, producing few false positives. High specificity is useful
for
,confirming a diagnosis after a positive screen. It is not equivalent to
sensitivity or unaffected by prevalence.
3. A negative result on a highly sensitive test is most useful for which purpose?
A) Confirming disease
B) Measuring prevalence
C) Ruling out disease
D) Predicting prognosis
Correct Answer: C) Ruling out disease
Rationale: A highly sensitive test has few false negatives, so a negative
result makes disease unlikely. This helps rule out a condition.
Confirmation is better with a highly specific test. Prevalence and
prognosis are not the primary uses.
4. Positive predictive value increases when which factor increases?
A) Specificity only
B) Sensitivity only
C) Test cost
D) Disease prevalence
Correct Answer: D) Disease prevalence
Rationale: Positive predictive value depends on sensitivity, specificity,
and disease prevalence. As prevalence increases, the proportion of
positive tests
,that are true positives rises. Cost does not affect predictive value.
Sensitivity and specificity also influence but prevalence is a key
determinant.
5. A complete blood count shows MCV 105 fL. This is classified as:
A) Macrocytic anemia
B) Microcytic anemia
C) Normocytic anemia
D) Thrombocytosis
Correct Answer: A) Macrocytic anemia
Rationale: Mean corpuscular volume above 100 fL indicates macrocytic
anemia. Common causes include vitamin B12 and folate deficiency.
Microcytic anemia has MCV below 80 fL, and normocytic anemia has MCV
80 to 100 fL. Thrombocytosis is an elevated platelet count.
6. A 72-year-old patient with fatigue has MCV 108 fL, low serum
B12, and positive anti-intrinsic factor antibodies. What is the likely
diagnosis?
A) Folate deficiency
B) Pernicious anemia
C) Iron deficiency anemia
D) Anemia of chronic disease
Correct Answer: B) Pernicious anemia
, Rationale: Pernicious anemia is caused by vitamin B12 deficiency due to
lack of intrinsic factor. Positive anti-intrinsic factor antibodies are highly
specific. The macrocytic anemia and low B12 support this diagnosis rather
than folate, iron, or chronic disease.
7. Which test best distinguishes vitamin B12 deficiency from folate deficiency?
A) Homocysteine
B) Ferritin
C) Methylmalonic acid
D) Reticulocyte count
Correct Answer: C) Methylmalonic acid
Rationale: Both B12 and folate deficiency elevate homocysteine, but only
B12 deficiency elevates methylmalonic acid. Therefore methylmalonic acid
best distinguishes the two. Ferritin evaluates iron status, and reticulocyte
count reflects red cell production.
8. A patient has microcytic anemia with low ferritin and high TIBC.
Which diagnosis is most likely?
A) Anemia of chronic disease
B) Thalassemia trait
C) Sideroblastic anemia
D) Iron deficiency anemia
Correct Answer: D) Iron deficiency anemia
