A CBC for a 10-year-old shows decreased MCHC and decreased MCV. Differential diagnosis should include which condition?

A CBC for a 10-year-old shows decreased MCHC and decreased MCV. Differential diagnosis should include which condition?

• A. Sickle cell anemia
• B. Vitamin B12 deficiency anemia
• C. Pernicious anemia
• D. Iron deficiency anemia

Answer: (D)

When both MCV and MCHC are decreased, you’re looking at a microcytic, hypochromic anemia. In children, the most common cause of this pattern is iron deficiency anemia, reflecting depleted iron stores from rapid growth and often limited dietary iron or blood loss. The red cells become smaller and paler because they have less hemoglobin. The other conditions listed don’t fit this pattern. Vitamin B12 deficiency and pernicious anemia produce macrocytic anemia with increased MCV, so the cells are larger. Sickle cell disease usually presents with normocytic, normochromic anemia, and the distinctive sickled cells are seen on smear rather than a consistent decrease in MCV and MCHC.

When both MCV and MCHC are decreased, you’re looking at a microcytic, hypochromic anemia. In children, the most common cause of this pattern is iron deficiency anemia, reflecting depleted iron stores from rapid growth and often limited dietary iron or blood loss. The red cells become smaller and paler because they have less hemoglobin.

The other conditions listed don’t fit this pattern. Vitamin B12 deficiency and pernicious anemia produce macrocytic anemia with increased MCV, so the cells are larger. Sickle cell disease usually presents with normocytic, normochromic anemia, and the distinctive sickled cells are seen on smear rather than a consistent decrease in MCV and MCHC.