What Are Basophils in a Blood Test?

Basophils are the rarest white blood cell, comprising less than 1% of WBCs. They release histamine in allergic reactions.

Normal Range

  • 0.5–1% of WBC
  • Absolute: 0–300/µL

High Basophils

  • Allergic reactions
  • Myeloproliferative disorders (CML, polycythemia vera)
  • Chronic inflammation
  • Hypothyroidism

Low Basophils

  • Usually not clinically significant
  • Acute stress or infection
  • Corticosteroid use
Source: NLM MedlinePlus, American Association for Clinical Chemistry.

Order a comprehensive metabolic panel online — private, no specialist referral required.

Order a comprehensive metabolic panel online ↗ affiliate link