Genotype test haemoglobin electrophoresis
Written for Veritas Pharmacy and Private Clinic, Sunderland, and reviewed by Titilayo Owolana, Superintendent Pharmacist, General Pharmaceutical Council registration number 2071462.
AA, AS, SS, SC: genotype results are usually written as a pair of letters, and knowing what they mean matters, especially before starting a family. Many people, particularly within West African and Caribbean communities, check genotype compatibility with their partner before marriage. This guide explains what your results mean, and why this simple blood test matters so much for family planning.
What is a genotype test?
Haemoglobin is the part of your blood that carries oxygen around your body. Most people carry a type called haemoglobin A. Some people also carry other types, such as haemoglobin S or haemoglobin C. A genotype test, also called a haemoglobin electrophoresis test, looks closely at your blood to find out exactly which types of haemoglobin you have.
Why do people get a genotype test?
Knowing your genotype is useful information about your own health, and it is especially important when planning a family. If two parents both carry a variant type of haemoglobin, there is a chance their child could inherit a condition such as sickle cell disease. Because of this, checking genotype compatibility before marriage or before starting a family is a well established and important practice in many communities.
What happens during the test
A genotype test is simple and works in the same way as any other blood test.
- A small blood sample is taken. A trained clinician will take a small sample of blood, usually from your arm, in the same gentle way as any other blood test.
- Your sample is analysed. The blood is examined closely to identify the different types of haemoglobin present.
- You receive your results. Your clinician will explain your results to you clearly, and answer any questions you have.
What do the results mean?
Genotype results are usually written as a pair of letters. Here are some of the most common results and what they generally mean.
- AA. This is the most common result. It means you carry only the usual type of haemoglobin.
- AS. This means you carry one usual type of haemoglobin and one sickle type. This is often called being a carrier, or having sickle cell trait. Most people with this result do not have any symptoms.
- SS. This means both of your haemoglobin genes carry the sickle type. This result is linked to sickle cell disease, and your clinician will talk you through what this means and the support available.
- SC. This means you carry one sickle type and one C type of haemoglobin. Your clinician can explain what this means for you in more detail.
- AC. This means you carry one usual type of haemoglobin and one C type. This is generally known as being a carrier of haemoglobin C.
Whatever your result, your clinician is there to explain it clearly and answer any questions, without any pressure.
You can find current pricing and book your appointment on our genotype test service page.
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Book Your AppointmentFrequently asked questions
What is the difference between a genotype test and a normal blood test?
A genotype test uses the same simple blood sample as any other blood test. The difference is in what happens afterwards, as the sample is examined closely to identify the types of haemoglobin you carry.
Why do people check genotype before marriage?
If both partners carry a variant type of haemoglobin, there is a chance their children could inherit a condition such as sickle cell disease. Checking genotype beforehand allows couples to understand this and talk to a clinician or genetic counsellor about their options.
Is a genotype test the same as a full genetic test?
A genotype test, or haemoglobin electrophoresis, looks specifically at the types of haemoglobin in your blood. It is a well established and reliable way of finding this out, though your clinician can advise you if any further genetic testing would be helpful in your situation.
What happens if my result shows I am a carrier?
Being a carrier, such as having an AS result, usually does not affect your own health. It is still useful and important information, particularly if you are planning a family, and your clinician can talk you through what it means.
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