Sickle cell variants	Hemoglobin electrophoresis (< 2 months of age)†	Serial complete blood count, reticulocyte count	Hematologic studies (9 months of age)			Parents' usual phenotypes∥
			MCV‡	Hemoglobin A2 (%)§	Hemoglobin F (%)§	DNA dot blot	One parent	Other parent
Homozygous sickle cell disease, or hemoglobin SS disease	FS	Hemolysis and anemia usually by 6 to 12 months of age	Normal or increased	<3.6	< 25	βS	AS	AS
Sickle β0-thalassemia	FS	Hemolysis and anemia usually by 6 to 12 months of age	Decreased	>3.6	< 25	βAβS	AS	A on routine electrophoresis
								A2 > 3.6 on quantitative electrophoresis
								F increased on quantitative electrophoresis
								MCV decreased on hemogram
Sickle β+-thalassemia	FSA	Mild anemia or no anemia by 2 years of age	Normal or decreased	>3.6	<25	βAβS	AS	A on routine electrophoresis
								A2 > 3.6 on quantitative electrophoresis
								MCV decreased on hemogram
Hemoglobin SC disease	FSC	Mild anemia or no anemia by 2 years of age	Normal or decreased	Not applicable	<15	βSβC	AS	AC