| anisocytosis | variation in cell size | corresponds to raised RDW (see Full Blood Count) | 
 | poikilocytosis | variation in cell shape | may be diagnostic (e.g. spherocytes) | 
 | macrocytosis | raised red cell volume | B12/folate deficiency, ethanol, hypothyroidism | 
 | microcytosis | reduced red cell volume | iron deficiency, thalassaemia trait | 
 | rouleaux | 'chains' of red cells | raised protein in plasma e.g. myeloma, inflammation | 
 | agglutination | 'clumped' red cells | col autoagglutination | 
 | spherocytes | small round red cells | hereditary, autoimmune | 
 | elliptocytes | rod shaped red cells | hereditary, elliptocytosis | 
 | target cells | dark centre to red cells | thalassaemia, liver disease, iron deficiency, Hb C (Afro-Caribbeans) | 
 | polychromasia | large basophilic red cells | immature red cells (bleeding, haemolysis) | 
 | Howell Jolly bodies | nuclear remnants in red cells | post-splenectomy, hyposplenism | 
 | Heinz bodies | denatured haemoglobin | oxidative haemolysis (e.g. G6PD deficiency) | 
 | Burr cells | irregularly crenated red cells | renal failure, hypothyroidism | 
 | acanthocytes | spiky red cells | liver disease | 
 | schistocytes | red cell fragments | mechanical e.g. prosthetic heart valves, DIC | 
 | left shift | myelocytes and meta-myelocytes in film | infection, marrow infiltration | 
 | right shift | hypersegmented polymorphs | megaloblastic anaemia | 
 | toxic granulation | increased granulation in neutrophils | implies bacterial infection |