Acquired hemolytic anemia
Acquired hemolytic anemia can be divided into immune and non-immune mediated forms of hemolytic anemia.

# Immune
Immune mediated hemolytic anemia (direct Coombs test is positive)
- Autoimmune hemolytic anemia
Warm antibody autoimmune hemolytic anemia
Idiopathic
Systemic lupus erythematosus (SLE)
Evans' syndrome (antiplatelet antibodies and hemolytic antibodies)
Cold antibody autoimmune hemolytic anemia
Idiopathic cold hemagglutinin syndrome
Infectious mononucleosis and mycoplasma ( atypical) pneumonia
Paroxysmal cold hemoglobinuria (rare)
- Warm antibody autoimmune hemolytic anemia
Idiopathic
Systemic lupus erythematosus (SLE)
Evans' syndrome (antiplatelet antibodies and hemolytic antibodies)
- Idiopathic
- Systemic lupus erythematosus (SLE)
- Evans' syndrome (antiplatelet antibodies and hemolytic antibodies)
- Cold antibody autoimmune hemolytic anemia
Idiopathic cold hemagglutinin syndrome
Infectious mononucleosis and mycoplasma ( atypical) pneumonia
Paroxysmal cold hemoglobinuria (rare)
- Idiopathic cold hemagglutinin syndrome
- Infectious mononucleosis and mycoplasma ( atypical) pneumonia
- Paroxysmal cold hemoglobinuria (rare)
- Alloimmune hemolytic anemia
Haemolytic disease of the newborn (HDN)
Rh disease (Rh D)
ABO hemolytic disease of the newborn
Anti-Kell hemolytic disease of the newborn
Rhesus c hemolytic disease of the newborn
Rhesus E hemolytic disease of the newborn
Other blood group incompatibility (RhC, Rhe, Kidd, Duffy, MN, P and others)
Alloimmune hemolytic blood transfusion reactions (ie from a non-compatible blood type)
- Haemolytic disease of the newborn (HDN)
Rh disease (Rh D)
ABO hemolytic disease of the newborn
Anti-Kell hemolytic disease of the newborn
Rhesus c hemolytic disease of the newborn
Rhesus E hemolytic disease of the newborn
Other blood group incompatibility (RhC, Rhe, Kidd, Duffy, MN, P and others)
- Rh disease (Rh D)
- ABO hemolytic disease of the newborn
- Anti-Kell hemolytic disease of the newborn
- Rhesus c hemolytic disease of the newborn
- Rhesus E hemolytic disease of the newborn
- Other blood group incompatibility (RhC, Rhe, Kidd, Duffy, MN, P and others)
- Alloimmune hemolytic blood transfusion reactions (ie from a non-compatible blood type)
- Drug induced immune mediated hemolytic anemia
Penicillin (high dose)
Methyldopa
- Penicillin (high dose)
- Methyldopa

# Non-immune
Non-immune mediated hemolytic anemia (direct Coombs test is negative)
- Drugs (i.e., some drugs and other ingested substances lead to haemolysis by direct action on RBCs, e.g. ribavirin )
- Toxins (e.g., snake venom; plant poisons such as aesculin)
- Trauma
Mechanical (heart valves, extensive vascular surgery, microvascular disease)
- Mechanical (heart valves, extensive vascular surgery, microvascular disease)
- Microangiopathic hemolytic anemia (a specific subtype with causes such as TTP, HUS, DIC and HELLP syndrome)
- Infections (Note: Direct Coombs test is sometimes positive in hemolytic anemia due to infection)
Malaria
Babesiosis
Septicaemia
- Malaria
- Babesiosis
- Septicaemia
- Membrane disorders
Paroxysmal nocturnal hemoglobinuria (rare acquired clonal disorder of red blood cell surface proteins)
Liver disease
- Paroxysmal nocturnal hemoglobinuria (rare acquired clonal disorder of red blood cell surface proteins)
- Liver disease

# Drug induced hemolysis
Drug induced hemolysis has large clinical relevance.  It occurs when drugs actively provoke red blood cell destruction. It can be divided in the following manner:
- Drug-induced autoimmune hemolytic anaemia
- Drug-induced nonautoimmune hemolytic anaemia
A total of four mechanisms are usually described, but there is some evidence that these mechanisms may overlap.