Morphologic Classification & the Red Blood Cell Distribution Width

Question 1

The RDW can help determine the cause of an anemia when used in conjunction with the __________

Answer 1

MCV

Question 2

Each of the three MCV categories (normocytic, microcytic, macrocytic) can also be subclassified by the RDW as _____________ (normal RDW) or __________ (increased or high RDW).

Answer 2

homogeneous, heterogeneous

Question 3

“RDW Normal”
Decreased: _______________
Normal: ______________
Increased: ________________

Answer 3

Decreased:
α or β-Thalassemia trait
Anemia of chronic inflammation
Hb E disease/trait

Normal:
Anemia of chronic inflammation
Anemia of renal disease
Acute hemorrhage
Hereditary spherocytosis

Increased:
Aplastic anemia
Chronic liver disease
Alcoholism
Chemotherapy

Question 4

“RDW Increased”
Decreased: _______________
Normal: ______________
Increased: ________________

Answer 4

Decreased:
Iron deficiency
Sickle cell-β-thalassemia

Normal:
Early iron, folate, or vitamin B12 deficiency
Mixed deficiency of iron ( vitamin B12 or folate
Sickle cell anemia
Hb SC disease
Myelodysplastic syndromes

Increased:
Folate or vitamin B12 deficiency
Myelodysplastic syndromes
Cold agglutinin disease
Chronic liver disease
Chemotherapy

Question 5

“Anemia Caused by Decreased Production of Red Blood Cells”

It is acquired and congenital aplastic anemia, pure red cell aplasia, anemia associated with marrow infiltration (myelophthisic)

Answer 5

Bone Marrow failure

Question 6

“Anemia Caused by Decreased Production of Red Blood Cells”

Impairment of erythroid development:

Answer 6

• Disorders of DNA synthesis: megaloblastic anemia
• Disorders of hemoglobin synthesis: iron deficiency anemia, thalassemia, sideroblastic anemia, anemia of chronic inflammation
• Decreased production of erythropoietin: anemia of renal disease

Question 7

“Anemia Caused by Increased Red Blood Cell Destruction or Loss”

Intrinsic RBC abnormality:

Answer 7

• Membrane defects: hereditary spherocytosis, hereditary elliptocytosis or pyropoikilocytosis, paroxysmal nocturnal hemoglobinuria
• Enzyme deficiencies: glucose-6-phosphate dehydrogenase deficiency, pyruvate kinase deficiency
• Globin abnormalities: sickle cell anemia, other hemoglobinopathies

Question 8

“Anemia Caused by Increased Red Blood Cell Destruction or Loss”

Extrinsic RBC abnormality:

Answer 8

• Immune causes: warm-type autoimmune hemolytic anemia, cold agglutinin disease, paroxysmal cold hemoglobinuria, hemolytic transfusion reaction, hemolytic disease of the fetus and newborn
• Nonimmune red blood cell injuries: microangiopathic hemolytic anemia (thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, HELLP syndrome, disseminated intravascular coagulation), macroangiopathic hemolytic anemia (traumatic cardiac hemolysis), infectious agents (malaria, babesiosis, bartonellosis, clostridial sepsis), other injury (chemicals, drugs, venoms, extensive burns)

Question 9

It is defined operationally as a reduction in the hemoglobin content of blood that can be caused by a decrease in the red blood cell (RBC) count, hemoglobin concentration, and hematocrit below the reference interval for healthy individuals

Answer 9

Anemia

Question 10

A thorough physical examination is valuable in determining the cause of anemia. Some of the areas that should be evaluated are ________, ________, ________, ________, ________, ________, ________, ________, and ________

Answer 10

skin, nail beds, eyes, mucosa, lymph nodes, heart,
spleen, and liver

Question 11

___________ (hemoglobin concentration between 7 and 10 g/dL) may cause pallor of conjunctivae and nail beds, but not manifest other clinical symptoms if the onset is slow.

Answer 11

Moderate anemias

Question 12

_____________ (hemoglobin concentration of less than 7 g/dL) usually produce pallor, dyspnea, vertigo, headache, muscle weakness, lethargy, hypotension, and tachycardia.

Answer 12

Severe anemias

Question 13

Laboratory procedures helpful in the initial diagnosis of
anemia include the ________, ________, and ________.

Answer 13

complete blood count (CBC) with RBC indices, red blood cell distribution width (RDW) and the reticulocyte count, and examination of the peripheral blood film

Question 14

_____________ examination is usually not required for diagnosis of anemia but is indicated in cases of unexplained anemia, fever of unknown origin, or suspected hematologic neoplasm.

Answer 14

Bone marrow

Question 15

The __________ and _________ play crucial roles in investigation of the cause of an anemia

Answer 15

reticulocyte count and mean cell volume (MCV)

Question 16

The MCV, when combined with the ___________ and ___________, also can aid in classification of anemia.

Answer 16

reticulocyte count and the RDW

Question 17

Major subgroups of the pathophysiologic classification include anemias caused by__________ and those caused by

Answer 17

decreased RBC production, increased RBC destruction or acute blood loss