Spherocytisis

It is autosomal dominant in which there is a mutation in spectrin/ankyrin in cell membrane. Microvesicles form on surface in areas of weakness and are lost [ so there is a decrease in surface/volume ratio]. So RBC loses  potassium + water and in result become dehydrated. Black calcium bilirubinate stones [calcium bilirubinate deconjugated to unconjugated bilirubin which binds to calcium]. On a slide, if you do not see a central pallor  therefore it must be a spherocyte and should be removed extravascularly. In this disease, we always see splenomegaly over the period of time. Gallbladder disease is common because there is a lot more unconjugated bilirubin presented to the liver and more conjugation is occuring and more bilirubin is in the bile than usual. Diagnostic test used here is osmotic fragility test that put the RBC wall to wall in different tonicities of saline, and it shows the RBC. Eventually splenectomy is needed. This its a intrinsic extravascular hemolytic anemia.