Blood film interpretation

Term	Meaning	Possible Significance
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
shistocytes	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