**Question:** Case history of peripheral smear is showing hypersegmented neutrophils, this is due to deficiency of

A. Vitamin C
B. Vitamin B12
C. Vitamin D
D. Vitamin E

**Correct Answer:**

**Core Concept:** Hypersegmented neutrophils are neutrophils with an increased number of lobes (more than the normal 3-5 lobes) on a peripheral blood smear. This can be observed in conditions affecting neutrophil maturation or function.

**Why the Correct Answer is Right:** Hypersegmented neutrophils are typically seen in conditions affecting neutrophil maturation, such as vitamin deficiencies. Vitamin B12 (cobalamin) deficiency is known to cause macrocytic anemia and hypersegmented neutrophils due to impaired neutrophil maturation and function.

**Why Each Wrong Option is Incorrect:**

A. Vitamin C deficiency: Although vitamin C is essential for collagen synthesis and immune function, it does not directly affect neutrophil maturation or function. Hypersegmented neutrophils are not a common feature of vitamin C deficiency.

B. Vitamin B12 deficiency: As mentioned earlier, the correct answer. Vitamin B12 deficiency causes macrocytic anemia and hypersegmented neutrophils due to impaired neutrophil maturation and function.

C. Vitamin D deficiency: Vitamin D plays a role in calcium homeostasis, bone health, and immune function. Although it might affect neutrophil function indirectly, hypersegmented neutrophils are not a common feature of vitamin D deficiency.

D. Vitamin E deficiency: Vitamin E is an antioxidant and plays a role in immune function. Although it might affect neutrophil function indirectly, hypersegmented neutrophils are not a common feature of vitamin E deficiency.

**Clinical Pearl:** A thorough clinical examination, including a complete blood count (CBC) with differential, is essential in evaluating patients presenting with abnormal blood smears. This can help identify specific deficiencies and guide appropriate management.