Sickle Cell Genotype (AA, AS, SS)

This test determines your sickle cell status through a detailed analysis of the haemoglobin in your blood, using haemoglobin electrophoresis (HPLC). Haemoglobin is the protein in red blood cells that carries oxygen around the body, and it comes in several forms. As well as identifying whether you carry the sickle cell trait or have a sickle cell condition, this test measures your haemoglobin types and includes an assessment of thalassaemia, giving a fuller picture of your inherited haemoglobin makeup.

What it can help assess

• Sickle cell status: identifying whether you have normal haemoglobin, carry the sickle cell trait, or have a sickle cell condition
• Thalassaemia: the test also assesses for beta-thalassaemia (from your haemoglobin levels) and alpha-thalassaemia (from your red cell indices)
• Other haemoglobin variants: detecting other inherited variants, such as haemoglobin C, where present
• Family planning: understanding your status is valuable when planning a family, as two carriers can have a child with a more serious condition

What is measured

• Haemoglobin types: including HbA, HbA2, HbF, HbS, HbC, and other fractions
• Overall genotype: for example AA (normal), AS (sickle cell trait), or SS (sickle cell disease)
• Red cell indices: red blood cell count, haemoglobin level, and cell size (MCV and MCH), which support the assessment of thalassaemia
• Thalassaemia status: an assessment of beta- and alpha-thalassaemia

An important note on interpretation

The haemoglobin levels and red cell indices are considered together to build the overall picture. Beta-thalassaemia is assessed mainly from a raised HbA2 level, while alpha-thalassaemia is not detected directly by this method and is instead suggested by the pattern of your red cell indices, which would need a separate genetic (DNA) test to confirm. Any significant result is best discussed with your GP, and where relevant, genetic counselling can help explain what it means for you and your family.

Why it matters

Sickle cell and thalassaemia are among the most common inherited conditions worldwide, and knowing your status is valuable both for your own health and for family planning. If you and your partner both carry a trait, there is a chance of having a child with a more serious condition, which is why many couples choose to check their status before or during pregnancy. Understanding your haemoglobin makeup provides useful information to guide your care and any further advice.

Haemoglobin Types
- Haemoglobin A (HbA)
- Haemoglobin A2 (HbA2)
- Haemoglobin F (HbF)
- Haemoglobin S (HbS)
- Haemoglobin C (HbC)
- Other fractions

Genotype & Thalassaemia
- Overall haemoglobin genotype (e.g. AA, AS, SS)
- Beta-thalassaemia status
- Alpha-thalassaemia status (from red cell indices)

Red Cell Indices
- Red blood cell count (RBC)
- Haemoglobin (HGB)
- Mean corpuscular volume (MCV)
- Mean corpuscular haemoglobin (MCH)

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.