What does a hemoglobin (Hb) electrophoresis result showing hemoglobin S (HbS) at 6.3% with normal other parameters indicate?

Interpretation of Hemoglobin S 6.3% on Hemoglobin Electrophoresis

A hemoglobin electrophoresis result showing hemoglobin S (HbS) at 6.3% with normal other parameters indicates sickle cell trait (heterozygous carrier state for sickle cell disease). 1

Understanding Sickle Cell Trait

• Sickle cell trait (HbAS) occurs when an individual inherits one sickle hemoglobin gene and one normal hemoglobin gene, resulting in both normal hemoglobin (HbA) and sickle hemoglobin (HbS) in their red blood cells 1
• In sickle cell trait, HbS typically constitutes 35-45% of the total hemoglobin, while in this case the percentage is much lower at 6.3%, which still represents the carrier state 1
• The presence of HbS at this percentage with otherwise normal parameters indicates heterozygosity for the sickle cell gene mutation 1

Clinical Significance

• Sickle cell trait is generally a benign condition that rarely causes clinical symptoms under normal circumstances 1
• Unlike sickle cell disease (HbSS), which causes significant morbidity and mortality, sickle cell trait typically does not require specific medical interventions 1
• Individuals with sickle cell trait have normal hemoglobin levels and red blood cell indices, and do not experience the vaso-occlusive crises characteristic of sickle cell disease 1

Important Considerations

• Genetic counseling is recommended for individuals with sickle cell trait, as they have a 50% chance of passing the sickle cell gene to each child 1
• If both parents have sickle cell trait, there is a 25% chance their child will have sickle cell disease 1
• In rare circumstances, individuals with sickle cell trait may experience complications under extreme conditions such as:
  • Severe dehydration 1
  • High altitude exposure 1
  • Extreme physical exertion 1

Diagnostic Considerations

• Hemoglobin electrophoresis is the standard method for diagnosing hemoglobinopathies, including sickle cell trait 1
• The finding of 6.3% HbS should be documented in the patient's medical record and discussed with the patient 1
• This information should be rediscussed during adolescence and at transition to adult care to ensure the patient understands the implications for family planning 1

Follow-up Recommendations

• No specific treatment is required for sickle cell trait 1
• Patient education about the genetic implications is important 1
• Consider screening other family members, particularly siblings who may also have inherited the trait 1
• Document this finding in the medical record to avoid unnecessary repeat testing in the future 1