What does a normal RBC, Hgb, Hct, slightly low MCV, normal RDW, and normal Lymphocyte count indicate in a 4-year-old?

Normal Complete Blood Count in a 4-Year-Old Child

These laboratory values are entirely normal for a 4-year-old child and require no further evaluation or intervention.

Interpretation of Individual Parameters

Red Blood Cell Indices

• RBC count (4.92 × 10¹²/L): This is normal for a 4-year-old child 1
• Hemoglobin (14.1 g/dL): This is well within the normal range and excludes anemia 1
• Hematocrit (42.1%): This is normal and consistent with the hemoglobin value 1

Mean Corpuscular Volume (MCV 85.6 fL)

• The MCV of 85.6 fL is normal for a 4-year-old, as MCV gradually increases during childhood from lower values in infancy toward adult levels 1
• While this value might appear at the lower end of the reference range, it is age-appropriate and does not indicate microcytosis 2
• The normal RDW (12.5%) confirms that this is not pathologic microcytosis, as conditions like thalassemia minor would show low MCV with normal/low RDW (≤14.0%), but the MCV here is not actually low 1, 2

Red Cell Distribution Width (RDW 12.5%)

• This RDW is normal (well below the 14.0% threshold that represents the 95th percentile) 1, 2
• Normal RDW indicates a homogeneous red cell population with minimal variation in cell size 2
• This normal RDW effectively rules out iron deficiency anemia, which typically presents with elevated RDW (>14.0%) due to increased variation in red cell size 1, 3

Lymphocyte Count (5.39 × 10⁹/L)

• This absolute lymphocyte count is normal for a 4-year-old child 1
• Young children normally have higher lymphocyte counts than adults, and this value falls within expected pediatric ranges 1

Clinical Significance

No further testing or intervention is needed based on these results. The combination of:

• Normal hemoglobin and hematocrit (excluding anemia) 1
• Age-appropriate MCV 1, 2
• Normal RDW (excluding iron deficiency and hemoglobinopathies) 1, 2, 3
• Normal lymphocyte count 1

indicates healthy hematopoiesis and immune function in this child.

Key Pitfalls to Avoid

• Do not misinterpret the MCV as "low" without using age-appropriate reference ranges, as pediatric MCV values differ significantly from adult values 1, 2
• Do not initiate empiric iron supplementation when all parameters are normal, as this is unnecessary and potentially harmful 2
• Do not order hemoglobin electrophoresis or further hematologic workup when RDW is normal and MCV is age-appropriate, as this pattern excludes thalassemia and other hemoglobinopathies 1, 2