Week 4: Macrocytic Anemia
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Macrocytosis
Vitamin B12
Folic acid
Megaloblastic changes
Pernicious anemia
Schilling test
Hypersegmented PMN
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Bone marrow analysis
WBC precursors
Liver disease
Polycythemia and
erythremia
PV
Newborn CBC
Bone Marrow Analysis
Aspirate
 Particles in fluid part of marrow
 Differential count
 Biopsy
 Solid part of the marrow
 Cellularity
 Clot section
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Aspiration
Biopsy
WBC Precursors
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Myeloblast
Promyelocyte
 Primary azurophilic granules
Meylocyte
 Specific granules
Metamyelocyte
Band, stab
Segmented neutrophil, PMN
Myeloblast
Promyelocyte
Neutrophilic
Myelocyte
Segmented neutrophil
and lymphocyte
Mast cell and histiocyte
Mast cell
Megakaryocyte
Plasma cell
Histiocyte
Fat cell
Macrophage
Osteoclasts
Osteoblasts
Giant cell
Non-Megaloblastic Macrocytosis
Alcoholism
 Poor nutrition
 Cirrhosis
 Liver disease
 Reticulocytosis
 Hemolytic anemia
 Hemorrhage
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Megaloblastic Anemia
Hemolytic changes
 Waxy pallor
 Neurologic changes with B12 deficiency
 Glossitis, beefy red or smooth pale tongue
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Causes of Megaloblastic Anemia
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Folate deficiency
 Dietary (green leafy vegetables)
 Malabsorption
B12 deficiency
 Dietary
 Fish tapeworm (D latum)
Pernicious anemia
 Lack of gastric intrinsic factor (IF) for
absorption
B12 Metabolism
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Bind to cobalophilin (cobalamine binding protein)
in saliva and gastric secretion
Bind to IF (from parietal cell) in the duodenum
Cbl-IF complex bind to receptor (cubilin) at distal
ileum for mucosal absorption
1% B12 can be absorbed without IF (megadose of
B12 for IF deficiency, no need for IV)
Autoimmune mechanism for PA
Megaloblastic Lab Changes
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MCV up to 140 fL
Howell-Jolly bodies
and Cabot rings
Hypersegmented PMN
Pancytopenia
BM with low M:E
ratio
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Megaloblastic
morphology (giant
bands and metas)
B12 and folate assays
RBC folate (long term
indicator)
IF antibody (PA)
Schilling test
(obsolete)
Hypersegmented PMN
Megaloblastic anemia
Megaloblastic BM
Other Apparent Macrocytoses
Cold agglutinin
 Prewarm samples
 Hyperglycemia
 Osmotic changes
 Clot
 Rouleaux
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Polycythemia Vera
A type of myeloproliferative disorder
(MPD)
 Independent of EPO
 High total RBC mass (by radio tagging)
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Secondary Polycythemia
Dehydration (decreased plasma volume)
 Increased O2 demand (e.g., emphysema,
high elevation)
 High EPO (e.g., kidney tumor)
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