Blood/Blood Cells and Cellular Components ›› Red Blood Cells ›› Abnormal Macrocytic RBC: MCV >100* Click Here for Full Size › Microscopic Features: Slightly larger than a normal mature RBC which correlates to the MCV of >100 fL Round to oval in shape (lacks a nucleus similar to the normal RBC) Cytoplasm is pink-orange in color wth a central pallor (similar to a normal RBC) › Normal % blood-PB, marrow-BM, lymphoid tissue-LN: PB: Rare to None BM: Rare to None LN: Rare to None › May Resemble: Normal Mature RBC Polychromatophilic RBC Giant platelet (specially if hypogranular) Elliptocyte (ovalocyte) › Differential Diagnoses: Vitamin B12 or folate deficiency Chemotherapy (e.g. Methotrexate) Liver disease Thyroid disease MDS › Classic Immunophenotype: N/A › Cartoon Image: Click and drag for direct comparison › Misc: Must rule out B12 or Folate deficiency