Red Cell Distribution Width (RDW) Overview

What is the reference range for RDW in newborns?

What does a wider than normal RBC histogram indicate?

At what age does RDW typically reach adult levels?

Which of the following conditions is associated with increased RDW?

What is a characteristic of hypochromic cells?

In which condition might you find both hypochromic and normochromic cells together?

Which grading of hypochromia indicates that the area of central pallor is 1/2 of the diameter?

What condition is typically associated with macrocytic MCV?

Red Cell Distribution Width (RDW)

RDW is a measure of variation in red blood cell (RBC) size.
Reference range for newborns is 14.2 to 19.9%.
If the RBC histogram is wider than normal, the RDW is abnormal.
RDW is markedly increased in newborns but gradually decreases to adult levels by 6 months of age.

Red Blood Cell (RBC) Size and RDW

RBC size can be assessed by Mean Corpuscular Volume (MCV).
Decreased (microcytic):
- Anemia of chronic inflammation (ACI)
- Iron deficiency anemia
Normal (normocytic): G6PD deficiency
Increased (macrocytic):
- Liver disease
- Megaloblastic anemia
- Sickle cell anemia

Anisochromia

General term for variation in RBC coloration.
Normally, RBCs have a central area of pallor approximately 1/3 the diameter.
Anisochromia may also mean presence of both hypochromic and normochromic cells in a blood smear.
Hypochromic cells:
- Central pallor > 1/3 of diameter
- Usually microcytic
Hypochromic cells may also be seen in sideroblastic anemias, or after a blood transfusion with normal cells and some weeks after iron therapy for iron deficiency anemia.

Grading of Hypochromia

1+: Area of central pallor = 1/2
2+: Area of central pallor = 2/3
3+: Area of central pallor = 3/4
4+: Thin rim of hemoglobin

This quiz explores Red Cell Distribution Width (RDW) and its significance in measuring red blood cell size variation. Key concepts include the reference ranges for newborns, how RBC size is assessed, and the implications of anisochromia in blood smears. Test your understanding of these important hematological parameters.