USMLE Step 1 Question (Hematology)
Understanding the peripheral smear.
The following is a high-yield USMLE Step 1 hematology question.
It is followed by a deep dive into each answer choice—the answer can be found at the bottom of the post.
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Good luck!
QUESTION:
A 66-year-old male with chronic kidney disease is seeing his nephrologist for a routine follow-up. He visited the clinic ten days ago due to symptoms of fatigue, pallor, and weakness, for which he was treated. As part of today's follow-up appointment, his blood is drawn and a peripheral smear is obtained:
Based on his peripheral smear, which of the following is true?
A. Myelopoiesis has increased
B. Erythropoiesis has increased
C. Band neutrophils have increased
D. Proinflammatory substance production is increased
E. His neutrophil count is most likely elevated
To see the answer, scroll to the bottom of the page. If you’re unsure or want to learn more about the answer choices, see the DEEP DIVE below.
DEEP-DIVE:
The peripheral smear demonstrates the presence of reticulocytes. Their presence in increased numbers typically indicates an upregulation of red blood cell production (erythropoiesis). This increase is often a response to anemia, particularly in patients with chronic diseases like chronic kidney disease (CKD), where erythropoietin production may be impaired. This leads to anemia that requires compensatory erythropoiesis once treatment is initiated or the patient's condition stabilizes.
A. Myelopoiesis has increased
This refers to the production of cells derived from the myeloid lineage (like white blood cells), which is not directly indicated by the presence of reticulocytes.
B. Erythropoiesis has increased
The peripheral smear findings support this option.
C. Band neutrophils have increased
Band neutrophils are immature white blood cells, and an increase would suggest an acute infection or inflammation.
D. Proinflammatory substance production is increased
This would be suggested by clinical signs of inflammation or specific lab markers, not reticulocytes.
E. His neutrophil count is most likely elevated
Elevated neutrophil count suggests an acute inflammatory or infectious process. This cannot be concluded from the presence of reticulocytes alone.
VERDICT: Given this patient’s history and laboratory findings, he is most likely experiencing erythropoiesis in response to his chronic kidney disease.
FINAL ANSWER: B. Erythropoiesis has increased
