What lab results would suggest a macrocytic anemia?

Macrocytic anemia is characterized by an increased mean corpuscular volume (MCV), which indicates that the red blood cells are larger than normal. This condition is often associated with deficiencies in essential nutrients, primarily vitamin B12 and folate. An increase in MCV occurs when there is impaired DNA synthesis during red blood cell production, which is commonly the result of these deficiencies.

In analyzing the correct choice, the presence of increased MCV alongside decreased levels of either folate or vitamin B12 strongly suggests macrocytic anemia. Folate and vitamin B12 are both vital for effective red blood cell maturation, and their deficiency leads to the production of larger and less functional red blood cells.

The presence of increased MCV is a diagnostic hallmark for identifying macrocytic anemia, while the decreased levels of essential hematopoietic nutrients confirm the underlying cause. Consequently, this combination makes it clear that the patient may be experiencing macrocytic anemia due to nutritional deficiency.

To summarize, the key indicators for macrocytic anemia are specifically the elevated MCV alongside low levels of either folate or vitamin B12, confirming the diagnosis.