If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Unit: Hematologic system diseases

About this unit

Blood acts as a highway for medicine, stops bleeding, fights infections, and much more. But things can go wrong with blood too! The many types of cells in blood means that blood diseases produce a variety of symptoms. Learn about blood diseases, how they are diagnosed, and the ways health professionals treat these conditions.