Blood film

A blood film or peripheral blood smear is a diagnostic test where blood is prepared by spreading it out very thinly on a microscopic slide. This is usually done by drawing another smaller slide over a drop of blood to spread it out. This causes a "feathering" effect as the blood layer gets thinner and this feathering is usually where the blood is examined under a microscope. After the blood is spread, it is left to dry and then "fixed" with methanol before it is studied under the microscope. In most cases, the fixed slide is also stained. The test is used to examine individual blood cells. It was formerly the way a blood count was performed until testing machinery changed the procedure. However, it is still used to look for abnormally shaped blood cells and certain parasites such as malaria and filaria.
Blood film at Wikipedia
Category:Medical tests