Page 545 - Hematology_ Basic Principles and Practice ( PDFDrive )

460 Part V Red Blood Cells

TABLE Normal Red Blood Cell Values
34.1
Red Blood Cell
Hemoglobin (g/dL) Hematocrit (%) Count (10 /L) MCV (fL) MCH (pg) MCHC (g/dL)
12
Age Mean –2SD Mean –2SD Mean –2SD Mean –2SD Mean –2SD Mean –2SD
Birth (cord blood) 16.5 13.5 51 42 4.7 3.9 108 98 34 31 33 30
1–3 days (capillary) 18.5 14.5 56 45 5.2 4.0 108 95 34 31 33 29
1 week 17.5 13.5 54 42 3.1 3.9 107 88 34 28 33 28
2 weeks 16.5 12.5 51 39 4.9 3.6 105 86 34 28 33 28
1 month 14.0 10.0 43 31 4.2 3.0 104 85 34 28 33 29
2 months 11.5 9.0 35 28 3.8 2.7 96 77 30 26 33 29
3–6 months 11.5 9.5 35 29 3.8 3.1 91 74 30 25 33 30
0.5–2 years 12.0 11.0 36 33 4.5 3.7 78 70 27 23 33 30
2–6 years 12.5 11.5 37 34 4.6 3.9 81 75 27 24 34 31
6–12 years 13.5 11.5 40 35 4.6 4.0 86 77 29 25 34 31
12–18 Years
Female 14.0 12.0 41 36 4.6 4.1 90 78 30 25 34 31
Male 18–49 years 14.5 13.0 43 37 4.9 4.5 88 78 30 25 34 31
Female 14.0 12.0 41 36 4.6 4.0 90 80 30 26 34 31
Male 15.5 13.5 47 41 5.2 4.5 90 80 30 26 34 31
MCH, Mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; MCV, mean corpuscular volume.
From Oski FA: Pallor. In Kaye R, Oski FA, Barness LA, editors: Core textbook of pediatrics, ed 3, Philadelphia, 1989, Lippincott, p 62.

TABLE Usefulness of the Reticulocyte Count in the Diagnosis a primary hematologic process, either hereditary or acquired. In
34.2 of Anemia a contrast, the most common causes of anemia in adults are iron
deficiency caused by blood loss or anemia caused by systemic illness
Diagnosis Value or malignancy (Table 34.3).
Hypoproliferative Anemias Absolute Reticulocyte Count
<75,000/µL Anemia in Children
Anemia of chronic disease
Anemia of renal disease Hypoproliferative anemia in children may be associated with either
Congenital dyserythropoietic anemias acquired or congenital etiologies. Acquired cases are most commonly
caused by nutritional deficiency but also include those caused by
Effects of drugs or toxins
acquired aplastic anemia, transient erythroblastopenia of childhood
Endocrine anemias (TEC), the anemia of acute inflammation, and marrow replacement
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Iron deficiency caused by malignancy. Congenital causes include Diamond-Blackfan
Bone marrow replacement anemia and other rare syndromes, including refractory sideroblastic
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anemia and the congenital dyserythropoietic anemias. Iron defi-
Maturation abnormalities Absolute reticulocyte count ciency may occur in children because of a diet that is rich in cow’s
<75,000/µL milk to the exclusion of other iron-containing foods. This is particu-
Vitamin B 12 deficiency larly common during the first 2 years of life. The anemia may be
Folate deficiency quite severe and may be associated with a mean corpuscular volume
Sideroblastic anemia (MCV) of 50 to 65 fL. Acquired aplastic anemia, as opposed to pure
RBC aplasia, is associated with bicytopenia or pancytopenia. TEC is
Appropriate response to blood loss or Absolute reticulocyte count an acquired disorder that generally occurs during the first 3 years of
nutritional supplementation ≥100,000/µL life in otherwise healthy children, although it can be seen in children
Hemolytic anemias Absolute reticulocyte count from 6 months to 10 years old. It is thought to have a viral or
≥100,000/µL immunologic cause and resolves without specific intervention. The
anemia of acute inflammation may be encountered in children who
Hemoglobinopathies
are hospitalized and is generally transient, resolving when the under-
Immune hemolytic anemias lying condition has improved. Leukemia may result in BM replace-
Infectious causes of hemolysis ment and is usually associated with abnormalities in other cell lineages
in addition to RBCs.
Membrane abnormalities
Hemolytic anemia in children is most commonly associated with
Metabolic abnormalities inherited disorders of hemoglobin or the RBC membrane. However,
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Mechanical hemolysis acquired causes such as autoimmune hemolytic anemia and micro-
a Note that reticulocyte counts in the range of 75,000 to 100,000/µL can angiopathic hemolytic anemia, particularly Shiga toxin–associated
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sometimes be associated with appropriate response to blood loss or hemolytic hemolytic uremic syndrome (HUS), also occur. In older children,
anemia. many etiologies of hemolytic anemia overlap with those considered
in adults, and a similar diagnostic algorithm may be appropriate.
However, in newborns, inherited causes of hemolytic anemia must
be distinguished from more pronounced cases of the physiologic