Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (299 page)

   Peripheral blood smear (PBS): visible sickle cells, polychromasia, and Howell-Jolly bodies in older children, reflecting hyposplenism due to autosplenectomy. Nucleated red cells, basophilic stippling, and Pappenheimer bodies are usually found.

   WBCs may be higher than normal. A persistent leukocytosis augurs a poor prognosis.

   Platelets may be elevated, in part the result of loss of splenic function.

   Bone marrow aspirate (not necessary for diagnosis) is hyperplastic.

   Serum erythropoietin may be inappropriately low in some patients, possibly as the result of progressive renal disease.

   Serum iron and ferritin may be low, and transferrin elevated, due to iron loss in urine.

   Serum folate is low due to overutilization, if not replaced therapeutically.

   Serum LDH is elevated.

   Serum bilirubin is commonly elevated.

   Serum haptoglobin is decreased.

   Serum aminotransferase is often elevated.

   Ferritin becomes very elevated in multiply transfused patients.

   Urine hemosiderin and urobilinogen are present (not necessary for diagnosis).