Vitamin B12 or Folate Deficiency: Although these deficiencies often lead to anemia, early stages or mild cases might present with elevated Mean Corpuscular Volume (MCV) without significant anemia. The body's stores and the gradual onset of deficiency can delay the development of anemia.

Alcohol Abuse: Chronic alcohol consumption can lead to an increase in MCV due to its toxic effect on the bone marrow, even in the absence of anemia. Alcohol also affects folate metabolism, which can contribute to elevated MCV.
Hypothyroidism: Some patients with hypothyroidism may have an elevated MCV without anemia. The mechanism is not fully understood but may relate to decreased metabolism and its effects on erythropoiesis.
Liver Disease: Certain liver diseases can cause an increase in MCV due to alterations in lipid metabolism and the production of lipoproteins that affect red blood cell membranes.

Myeloproliferative Neoplasms (MPN): Although less common, conditions like Polycythemia Vera or Essential Thrombocythemia can present with elevated MCV without anemia. These conditions are critical to diagnose due to their potential for thrombotic complications and transformation into more aggressive diseases.
Chronic Kidney Disease: Early stages of chronic kidney disease might present with elevated MCV due to the effects of uremia on red blood cell production and survival, even before anemia becomes apparent.

Ornithine Transcarbamylase Deficiency: A rare genetic disorder affecting the urea cycle, which can lead to elevated MCV among other symptoms, due to the accumulation of carbamoyl phosphate.
Phosphofructokinase Deficiency (Tarui's Disease): A glycogen storage disease that can cause an increase in MCV due to the abnormal accumulation of glycogen in red blood cells.
Hereditary Spherocytosis with Partial Splenectomy: Although typically associated with anemia, some cases with partial splenectomy might show an elevated MCV without significant anemia due to the removal of spherocytes and the spleen's reduced filtering capacity.