The page below is a sample from the LabCE course Normal Peripheral Blood Cells. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Normal Peripheral Blood Cells (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 94 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart

Eosinophil Function and Lifespan

Eosinophils have a circulating half-life of approximately 18 hours and a tissue life span of at least 6 days. They are capable of locomotion and phagocytosis and can enter inflammatory sites, but do so less readily than neutrophils. In tissues the primary location for eosinophils is in the epithelial barriers to the outside world such as, lungs, skin and GI tract. They are capable of returning to the circulating blood and bone marrow after they enter the tissues.
Eosinophils are active in parasitic infections and in allergic reactions such as asthma and hay fever, and may be present in great numbers in the peripheral blood during these conditions. Stress, shock, or burns may also cause an increase in this type of cell. Eosinophils modulate an allergic response by liberating substances which can neutralize mast cell and basophil products.
The image on the right shows malarial ring forms, which are parasites. This patient showed an increased eosinophil count due to his parasitic infection.