The clinical and laboratory phenotype of compensated haemolysis in a p
atient with hereditary ovalocytosis is reported. Clinical presentation
was intermittent jaundice and abdominal pain due to pigment gall ston
es. Haematological analysis revealed an absolute reticulocytosis with
an otherwise normal full blood count and biochemical evidence of haemo
lysis. Variable results were observed with blood grouping reagents. Th
e patient's red cells were stomatocytic ovalocytic, rigid, resistant t
o malarial parasite invasion, defective in anion transport, and had th
e characteristic two linked mutations in the red cell band 3 gene.