Basophils blood test
In short
A typical adult basophils result is 0 to 0.2 x10^3/µL. A slightly high count is uncommon and usually mild. It is most often linked to allergies, an underactive thyroid or ongoing inflammation. Always read your result against the range printed on your own report.
The rarest white blood cells, involved in allergic reactions.
Basophils are the least common white cells. They release histamine, a chemical behind allergy symptoms such as itching and sneezing. Because there are so few, small changes are common and usually mean little.
Is my Basophils high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults | 0–0.2 | x10^3/µL |
| Adults · percent of white cells | 0–1 | % |
Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.
If your Basophils is high
A slightly high count is uncommon and usually mild. It is most often linked to allergies, an underactive thyroid or ongoing inflammation.
Common reasons
- Allergies or a recent allergic reaction
- An underactive thyroid
- Ongoing inflammation, such as from a bowel condition
- Recovery from an infection, such as chickenpox
- Having had the spleen removed
- Less often: a bone marrow condition, such as chronic myeloid leukemia
What can throw it off
Because basophils are so few, a single count can swing by chance, so one high result is often just repeated.
Questions to take to your appointment
- 1Is this rise big enough to matter?
- 2Should my thyroid be checked?
- 3Should we repeat the count in a few weeks?
Read together with
Doctors rarely read Basophils alone. These usually sit next to it.
Quick answers
What is the basophils blood test?
Basophils: The rarest white blood cells, involved in allergic reactions. Basophils are the least common white cells. They release histamine, a chemical behind allergy symptoms such as itching and sneezing. Because there are so few, small changes are common and usually mean little.
What is a normal basophils level?
For most adults, basophils is typically 0 to 0.2 x10^3/µL. Some countries print it in %, so check the unit first. Labs differ a little, so the range printed next to your result is the one to go by.
What does a high basophils mean?
A slightly high count is uncommon and usually mild. It is most often linked to allergies, an underactive thyroid or ongoing inflammation. Common reasons include allergies or a recent allergic reaction; an underactive thyroid; ongoing inflammation, such as from a bowel condition; and recovery from an infection, such as chickenpox. A doctor reads it together with your other results and how you feel.
What can affect my basophils result?
Because basophils are so few, a single count can swing by chance, so one high result is often just repeated.
What should I ask my doctor about my basophils?
Questions worth taking to the appointment: Is this rise big enough to matter? Should my thyroid be checked? Should we repeat the count in a few weeks?
What this page can’t do
It reads each number on its own.
Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.
It doesn't know you.
Your age, your medicines, how you feel and your last result all change what a number means.
It doesn't remember.
Close this page and your results are gone. That's on purpose: nothing was ever sent to us.
We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.
Vita: Health Coach on the App StoreSources
- StatPearls — Complete blood count with differential
- ABIM — Laboratory test reference ranges (January 2026)
- MedlinePlus — Blood differential test
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.