Intrinsic factor, a glycoprotein secreted from paretal cells in the stomach, is responsible for forming a complex with cobalamin (B12) to then bind to an ileal receptor for absorption (1p1184). Lack of ability to secrete intrinsic factor results in pernicious anemia, a megaloblastic anemia from cobalamin deficiency(1;2). Pernicious anemia therapy often requires parenteral cobalamin or oral cobalamin in high enough doses (1).
Identifying megaloblastic anemia in a Complete Blood Count:
RBC - Decreases
Hb - Decreases
MCV - Increases
MCH - Stays the Same
MCHC - Stays the Same
1. Modern Nutrition in Health and Disease. Baltimore, MD: Lippincott Williams & Wilkins, 2009.
2. Saladino, C. "Week 1 Lecture, Part 1." Clinical Biochemistry [Lecture Series], 2009.
3. Medicine.net. "Complete Blood Count". Available at http://www.medicinenet.com/complete_blood_count/article.htm. Accessed on June 06, 2009.