Table 1.

Clinical and laboratory features of the vasoocclusive and hemolytic subphenotypes of sickle cell disease.^3–5

	Viscosity-vasoocclusion	Hemolysis-endothelial dysfunction
Laboratory	Lower LDH Higher PCV	Higher LDH Lower PCV
HbF	High HbF protective	HbF less protective
α Thalassemia	Absence of α thalassemia associated with increased viscosity	α thalassemia protective by reducing MCHC, erythrocyte density and hemolysis
Common clinical complications	1. Acute painful episodes. 2. Acute chest syndrome 3. Osteonecrosis.	1. Leg ulcer 2. Pulmonary hypertension 3. Priapism. 4. Stroke