Reference Ranges for Leukocytes and
Platelets
Hematology Review 291
BIRTH 1–2 MO 1–3 YR 8–13 YR ADULT COMMENTS
WBCs (× 10^9 /L) 9–37 6–18 5.5–17.5 4.5–13.5 4.5–11.5
Segs (%) 37–67 20–40 22–46 23–53 50–70
Bands (%) 3–11 0–5 0–5 0–5 0–5 Newborns: Occasional metas &
myelos. More immature grans in
preterm infants.
Lymphs (%) 18–38 42–72 37–73 23–53 18–42 Newborns: A few benign
immature B cells may be seen
(“baby” or “kiddie” lymphs).
PLT (× 10^9 /L) 150–450 150–450 150–450 150–450 150–450 Newborns: Variation in size &
shape.
Note trends and comparisons to adult values.