Abdominal pain and sicklemia in a patient with sickle cell trait.

We have presented a case of thrombotic thrombocytopenic purpura initially misdiagnosed as sickle cell crisis. Based on the "history" of hemoglobin S disease, anemia, and the presence of apparent sickled cells on the peripheral blood smear, the diagnosis of sickle cell crisis seemed reasonable. The patient is described because of unusual features of the case, to emphasize again a hazard of sickle cell screening and the value of reviewing the peripheral blood smear in cases of anemia.