In sickle cell trait, number of bands found in Hb –
In hemoglobin electrophoresis, various types of hemoglobin move at varying speed.
In sickle cell trait (heterozygous state), there are two types of hemoglobin - HbS (40%) and HbA (60%). So, on electrophoresis, two different bands are produced.
In Homozygous state, almost all hemoglobin is HbS. So, a single band is produced.

Laboratory findings of sickle cell anaemia

Moderate to severe anaemia
Peripheral smear will show
Sickle cells                
Target cells
A positive sickling test with a reducing substance like sodium metabisulfite.
Howell - Jolly bodies because of autosplenectomy
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