A 23 Year old female presents with anemia and jaundice for 2 years. Peripheral smear shows spherocytes. The best investigation to be done is :
High-Yield Explanation
Answer is C (Coombs test) Presence of anemia and jaundice together with spherocytes in peripheral smear is consistent with the diagnosis of both 'hereditary spherocytosis' and 'immunohemolytic anemias'. Coomb's test is the single best next investigation here as it will establish the above distinction. According to Harrisons text: 'Hereditary spherocytosis must be distinguished primarily from the spherocytic hemolytic anemias associated with RBC antibodies.' Coonzb's test is positive in immune spherocytic hemolytic anemias and it is negative in hereditroy spherocytosis. "The diagnosis of immune spherocytosis is readily established by a positive coomb's test. - Harrison "Coomb's test is negative in hereditary spherocytosis." CMDT 06 Osmotic fratgliti, test will be positive in both hereditary spherocytosis and immune spherocytic hemolytic anemias. "Increased osmotic fragility merely reflects the presence of spherocytes and does not distinguish hereditary spherocytosis, from other spherocytic hemolytic disorders such as autoimmune hemolytic anemia." - CMDT 06 / 491 Coomb's test is the single best next investigation here as it will establish the above distinction. Causes of spherocytes in peripheral smear / Spherocytic hemolytic anemia Hereditary spherocytosis. Immunohemolytic anemias (Autoimmune hemolytic anemias). In association with hemolysis induced by splenomegaly in patients with cirrhosis. Clostridial infections. Ceain snake envenomations. G6PD deficiency (few spherocytes).