Basophils %
The share of white blood cells that are basophils, the rarest type, involved in allergic reactions.
| Typical reference range | below 2 % |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Basophils contain histamine and other mediators released during allergic and inflammatory responses.
Why it matters
Basophils are usually 0-1% of white cells; persistent elevations can be a clue to allergic disease or, rarely, myeloproliferative disorders.
What a high result can mean
Mild increases occur with allergies, hypothyroidism and chronic inflammation; marked increases can occur in chronic myeloid leukemia and other myeloproliferative neoplasms.
What a low result can mean
Low basophils are normal and not clinically significant.
What affects the result
Interpret with the absolute basophil count.
Unit
Usually reported in %.
Also called on lab reports
Basophils, Basos, Baso %, Basophil %, Basophils (%), Basophils, Percent
Related tests: White Blood Cells & Differential
This page is educational and does not replace advice from a healthcare professional.