Hemato-pathology guide Flashcards
Red cell distribution width (RDW)
Standard deviation of the MCV
• Tells you how much the red blood cells differ from each other in size. If they are all pretty
similar in size, the RDW is low. If some are little and some are big, the RDW is high.
• Normal range = 12-13.5%
• Used to differentiate between anemias with minimal anisocytosis (difference in cell size)
(RDW 12-13.5%) and those with increased anisocytosis (RDW > 13.5%).
• You can see this on a blood smear: when anisocytosis is increased, you’ll see a range of
cell sizes – some are smaller, some are bigger.
Platelet count (Plt)
• Total number of platelets in blood
• Normal range = 150-450 x 109/L
• Causes of a low platelet count are numerous and include splenomegaly, idiopathic
thrombocytopenic purpura, disseminated intravascular coagulation, and bone marrow failure. Causes of a high platelet count are also numerous, and include reactive thrombocytosis (as seen in iron-deficiency anemia) and essential thrombocythemia.
anisocytosis
• Oval macrocytes (B12/folate deficiency)
• Microcytes (iron deficiency anemia, thalassemia)
• The size range can often help you narrow down which type of anemia is present
(for example, in iron-deficiency anemia, there is usually a big range of sizes)
poikilocytosis
- Schistocytes (microangiopathic hemolytic anemia)
- Spherocytes (hemolytic anemia, hereditary spherocytosis)
- Teardrop cells or dacryocytes (myelofibrosis or myelophthisic processes)
- Target cells or codocytes (hemoglobinopathies, thalassemias, liver disease)
- Sickle cells (sickle cell anemia)
- Echinocytes and acanthocytes (liver disease)
t(9;22)
CML
trisomy 12
CLL
t(8.21)
AML-M2
t(15;17)
AML-M3
inv(16)
AML-M4
11q23
AML-M4 and M5
t(11;14)
T-cell ALL
t(9;22)
B-cell precursor ALL
t(8;14)
B-cell ALL
Make too little blood
- Bad diet (not enough iron, B12, or folate)
- Decreased number of erythroblasts (as in aplastic anemia)
- Bone marrow full of other stuff besides hematopoietic precursors (e.g., tumor)
- Chronic disease (e.g., renal disease, inflammatory diseases)
Anemias with abnormally-sized red cells
- Red cells too small (microcytic) (iron-deficiency anemia, thalassemia)
- Red cells too big (macrocytic) (megaloblastic anemia)
Anemias with abnormally-shaped red cells
- Round red cells (spherocytes) (hereditary spherocytosis, autoimmune hemolytic anemia)
- Pointy red cells (sickle cell anemia, G6PD deficiency, microangiopathic hemolytic anemia)
- Target-shaped red cells (hemoglobinopathies, thalassemias)
Anemias with normal-looking red cells
• Increased reticulocytes (massive hemorrhage that occurred over 3 days ago)
• No increase in reticulocytes (recent massive hemorrhage, anemia of chronic disease,
aplastic anemia)
folate deficiency
Blood
• Macrocytic anemia (MCV >100)
• Oval macrocytes.
• Hypersegmented neutrophils.
Bone marrow
• Megaloblastic erythroblasts (BIG cells with big,
immature nucleus but maturing cytoplasm).
• Megaloblastic neutrophils and precursors.
• Giant metamyelocytes.
• Hypersegmented neutrophils.
Target cells
(thalassemias and hemoglobinopathies)
Schistocytes
microangiopathic hemolytic anemia
Signs of increased erythropoiesis
- Polychromatophilia (or, if stained with supravital stain, reticulocytosis)
- Basophilic stippling (RNA remnants not yet removed from cell)
- Nucleated red blood cells (bone marrow hurrying to get red cells out as quickly as possible)
Direct antiglobulin test (DAT)
Also called the Coomb’s test. Mix patient’s red cells with anti-human globulin (an antibody against human immunoglobulins). If the patient’s red cells are coated with antibodies (as they are in some immune processes, see later), the anti-human globulin will attach to those antibodies, bridging the red cells and making them clump together. So, a positive result (red cell clumping) means the patient’s red cells are coated with antibodies, and the hemolysis is probably immune-related.
