Quick Review Cards for Medical Laboratory Science

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.