Dyscrasias is a nonspecific term that refers to any disease or disorder. However, it usually refers to blood diseases.
Before modern medicine, it meant an imbalance of four body fluids: blood, bile, lymph, and phlegm.
Bain BJ. The peripheral blood smear. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 160.