Hematology & Oncology Command Center
High-yield hematology pathophysiology, algorithmic MCV-based anemia workups, peripheral blood smear cytology exhibits, coagulation cascade and mixing studies, leukemia and lymphoma cytogenetics, and plasma cell dyscrasias.
Microcytic Hypochromic Anemia Differential Matrix
| Condition | Serum Iron | Serum Ferritin | TIBC (Transferrin) | % Transferrin Saturation | Diagnostic Hallmark & Board Pearl |
|---|---|---|---|---|---|
| Iron Deficiency Anemia (IDA) | ↓↓ Low | ↓↓ Low (< 15 ng/mL) | ↑↑ High | ↓↓ Low (< 15%) | #1 cause worldwide. Increased RDW (anisocytosis); microcytic hypochromic RBCs with pencil cells; in adult males or postmenopausal females, always order colonoscopy to rule out occult GI malignancy! |
| Anemia of Chronic Disease (ACD) | ↓ Low | ↑ Normal to High | ↓ Low | Normal to ↓ (15–25%) | Inflammatory IL-6 stimulates hepatic production of Hepcidin → degrades ferroportin → traps iron inside macrophages and enterocytes, preventing release into circulation. |
| Thalassemia Trait (α or β) | Normal to High | Normal to High | Normal | Normal to High | Mentzer Index (MCV / RBC count) < 13 strongly favors thalassemia! Normal RDW; Target cells (codocytes) on smear; β-thalassemia trait shows elevated HbA2 (> 3.5%) on hemoglobin electrophoresis. |
| Sideroblastic Anemia | ↑↑ High | ↑↑ High | Normal to ↓ | ↑↑ High (> 50%) | Defect in heme synthesis (X-linked ALAS2, lead poisoning, alcoholism, isoniazid/vitamin B6 deficiency); Prussian blue stain of bone marrow reveals ringed sideroblasts (iron trapped in perinuclear mitochondria). |
Megaloblastic Anemia: Hypersegmented PMN
Cytological Clue: Neutrophil with ≥ 6 lobes (or ≥ 5% of neutrophils with 5 lobes) indicating impaired DNA synthesis with nuclear-cytoplasmic dyssynchrony.
B12 vs. Folate Differentiation:
- • Vitamin B12 Deficiency: Elevated Methylmalonic Acid (MMA) AND Homocysteine. Causes Subacute Combined Degeneration (SCD) of spinal cord (dorsal columns + lateral corticospinal tracts; ataxia + paresthesias).
- • Folate Deficiency: NORMAL MMA and elevated Homocysteine. No neurological deficits!
Hereditary Spherocytosis (HS)
Molecular Defect: Autosomal dominant mutation in RBC membrane skeleton proteins (Ankyrin, Spectrin, or Band 3) → membrane blebbing and loss of surface area → sphere-shaped RBCs without central pallor.
Triad & Labs: Hemolytic anemia, jaundice, and splenomegaly. Elevated MCHC (> 36%), negative direct Coombs test, and positive Eosin-5-maleimide (EMA) binding / acidified glycerol lysis test.
Definitive Treatment: Splenectomy (resolves hemolysis; spherocytes persist on smear, accompanied by newly visible Howell-Jolly bodies!).
