All of the following are normal peripheral blood RBC findings at ...

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All of the following are normal peripheral blood RBC findings at birth in a full-term infant except:
 
  a. Nucleated RBCs
  b. Mean cell volume (MCV) less than 90 fL
  c. Reticulocytosis of 5
  d. Hemoglobin of 20.2 g/dL

Question 2

What is the most likely reason that the red blood cell (RBC) count remains elevated in a newborn for the first 2 weeks of life?
 
  a. A relative loss of plasma occurs during the birth process.
  b. A significantly longer RBC life span increases the number of red cells in circulation.
  c. Partial anoxia exists in utero, and erythropoietin increases.
  d. The switch from fetal to adult hemoglobin causes number of red cells to increase.

[leeeep]

Answer to Question 1

ANS: B
An MCV of 90 fL in a newborn is abnormal and cause for a thalassemia/iron deficiency work-up. The mean MCV in a full-term newborn is 109 fL; an MCV less than 94 fL is cause for evaluation for a-thalassemia or iron deficiency. All the other results given are normal for a full-term newborn.

Answer to Question 2

ANS: C
Partial anoxia occurs in utero, which causes the normal physiologic response to increase erythropoietin, which stimulates erythropoiesis. About 2 weeks after birth, as the infant makes the transition from its placenta-dependent oxygenation to the increased tissue oxygenation of the lungs, erythropoietin decreases, and the red cell count begins to decrease.