Basophil percentage optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Basophil percentage:

  • Optimal 0 – 0.5 %; sufficient 0 – 1 %; out of range below 0 or above 1 %.

Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.

All units

UnitOptimalSufficientOut of range
%0 – 0.50 – 1below 0 or above 1

What the evidence says

The acceptable band of 0% to 1% is a published laboratory reference interval. The optimal ceiling of 0.5% has no published source; MedlinePlus gives 0.5% to 1% as normal. The percentage is normally small and is interpreted mainly when persistently raised, and the absolute basophil count is the more meaningful figure.

Sources

  • AUTO DIFF (test catalog entry) — MHCC Laboratory, test catalog powered by Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceAdult basophils 0% to 1%, the same as Sera's sufficient band. The page shows no review date; 2026 is the copyright year.
  • Blood differential test — MedlinePlus Medical Encyclopedia, US National Library of Medicine, 2025 · Government / public-health guidanceNormal basophils are 0.5% to 1% of white cells. Matches Sera's sufficient upper edge of 1%; 0.5% is its lower limit, not an optimal ceiling.

What Basophils % measures

The share of your white blood cells that are basophils.

Usually under 1%. A rise can point to allergies.

Related blood cell health markers

See Basophil percentage in the full list of biomarker ranges

About the author

Alina Radu is the founder of Sera and a software engineer. The idea started with her own Hashimoto's tests, scattered across years without the big picture. She is not a clinician: these ranges are compiled from the published sources linked on each page, with every source named. Alina Radu on LinkedIn

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.