Basophils (BASO%)

Basophil fraction of total white cells.

What it is

Normally <1% of total WBC. Elevated basophil percentage is rare and warrants haematology review.

Why it matters

Basophilia (>2%) can be a sign of a myeloproliferative neoplasm — particularly chronic myeloid leukaemia. Any persistent elevation should be investigated.

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

Below 1% of total WBC.

How often

Each blood count panel.