Eosinophils %
What it measures, and what changes the number.
This line shows eosinophils as a proportion of all white blood cells counted. Eosinophils are immune cells involved in allergy and in the response to parasites. The value comes from the white cell differential in a full blood count.
A percentage depends on the other white cell types too, so it is best read with the total white cell count and the absolute eosinophil count, which removes the effect of changes in other cell lines.
Eosinophils follow a daily rhythm and tend to be lower in the morning, so collection time can influence the figure. Counts are made on an EDTA sample by automated analysers, with manual review in some cases. Labs may print it as Eosinòfils or Eosinófilos %; note that a line labelled simply Eosinòfils may be the percentage rather than the absolute count, so the unit on the report is the best guide.
Often read alongside: Eosinophils, White blood cells, Neutrophils %, Lymphocytes %, Basophils %