Basophils (BASO#)

The rarest normal white cell — rarely clinically significant in isolation.

What it is

Basophils are the least common white blood cells and are involved in allergic reactions and inflammatory responses. They are rarely elevated and rarely clinically significant in isolation.

Why it matters

Basophil counts are included in complete blood count differentials as part of the full immune picture. Elevated basophils can occasionally signal myeloproliferative conditions — a finding to discuss with your haematologist if persistently elevated.

How to test

Full blood count differential.

This information is for educational purposes only. Always discuss testing and interpretation of results with your care team.

Optimal range

0.01–0.1 ×10⁹/L.

How often

Each blood count panel.