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Eosinophils are one of the types of white blood cells: they defend you against parasites, play a role in allergy and help keep inflammation in check. A result that is higher or lower than normal can point to many things, from an allergic reaction to a condition of the bone marrow, and does not always mean there is something wrong that needs care.[1]
On this page you can read what eosinophilic granulocytes are, what the guidelines say about a value that is too low or too high, what affects your value and which values are best looked at alongside it.
Also known as: eosinophils, eos, part of the full blood count with differential (white blood cell differential). At the lab: GBBX.
Eosinophils are one of the five types of white blood cells. White blood cells are also called leukocytes: they are made in your bone marrow and are found in your blood and in your lymphatic tissue, which is part of your lymphatic system.[1]
White blood cells are an important part of your immune system. When you are ill, they travel through your blood and tissue to where they are needed, and there they help your body defend itself.[1]
Eosinophils defend you against parasites, play a role in allergy and help keep inflammation in check. Your value comes from a blood count with differential, also called a white blood cell differential, which determines the amount or percentage of each type of white blood cell.[1]
The five types of white blood cells each do different work. By measuring them separately, your doctor gets important information about your health.[1]
A blood count with differential is often part of a routine check-up. Your doctor can also order the test to look for the cause of symptoms, such as unusual tiredness or weakness, or bruising without a clear cause.[1]
The test is also used to look further into an abnormal white blood cell count from an earlier blood test, and to follow how an existing blood condition develops during care.[1]
If your result is abnormal, your doctor may order other tests to find the cause. An abnormal result does not always mean something is going on that needs care.[1]
Labplusarts, the lab BioProfile works with, measures eosinophil granulocytes as a number per litre of blood, in 10^9/l. A widely used handbook for doctors gives 0 to 0.7 10^9/l as the usual range for adults. Your own result shows the range the lab uses for your test.[2]
| Value | What it means | Who it is for |
|---|---|---|
| 0 to 0.7 10^9/l[2] | Usual range | Adults |
Source: Harrison's Principles of Internal Medicine, normal white blood cell values in adults.[2]
MedlinePlus describes a low result in terms of a low white blood cell count: it can point to a bone marrow disorder, to certain medicines such as antibiotics, or to a condition that affects your immune system. Your doctor looks at a result like this alongside your symptoms, your medical history and your other blood values.[1]
A high number of white blood cells can point to an allergic reaction, to inflammation or an autoimmune condition, to a condition caused by germs, to a condition of the blood or the lymphatic system, or to the use of certain steroids. Here too, your doctor looks at the whole picture before reaching a conclusion.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
When you are ill, white blood cells move to the place where they are needed. Inflammation, an autoimmune condition and an allergic reaction go together with a higher number of white blood cells.[1]
Certain steroids go together with a higher number of white blood cells. Certain other medicines, such as antibiotics, go together with a lower number.[1]
MedlinePlus names smoking and alcohol use as factors that can affect your result, even when nothing is wrong.[1]
Severe stress and physical injury can also affect your result. That is why an abnormal result on its own says little.[1]
Eosinophils are included in all five packages, from BioProfile 31 to BioProfile 150.[3]
The BioProfile editorial team wrote this page on 1 October 2026 from the sources below, which we read on 1 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert is still to review this page; after that review, the expert's name and the date of the review will appear at the top. This page offers explanation, not a diagnosis. Discuss an abnormal value with your GP.
