Most blood tests are snapshots: they show how something looks today and may look different next year. A few are not like that. Your blood group, and the type of haemoglobin you inherited from your parents, stay the same for life. That makes the blood group test, the sickle cell screen and haemoglobin electrophoresis a little different from the rest of the catalogue. Most people only need them once, if at all, and usually for a clear reason.
Blood group
What it is
The NHS explains that there are four main blood groups, A, B, AB and O, determined by the genes you inherit from your parents. Each can be RhD positive or RhD negative, giving eight blood groups in total. The groups are defined by antigens, molecules on the surface of red blood cells, and by antibodies in the plasma. According to the NHS, almost half of the UK population (around 48%) has group O, and about 85% of people are RhD positive.
Why people want to know
LML describes the Blood Group test as identifying your ABO and Rh type. Its main medical uses are checking compatibility for blood transfusions and organ transplants, and pregnancy, where differences between the blood types of mother and baby can matter. The NHS notes that GPs do not routinely check people's blood group, which is why many adults simply do not know theirs. Some people want to know out of curiosity, for travel, or as part of planning a pregnancy.
A practical detail
LML asks for the blood group sample to be fresh and labelled by hand with your first name, family name, gender and date of birth. Because of this, a collection point or home phlebotomist is the usual route for this test.
Sickle cell
What it is
The NHS describes sickle cell disease as an inherited condition that affects red blood cells and can cause pain, swelling and tiredness. It happens when a person inherits a particular haemoglobin variant from both parents. Red cells containing this haemoglobin can change into a crescent, or sickle, shape, which affects how they flow and how long they last (Kato et al., 2018).
A person who inherits the variant from only one parent is a carrier, sometimes called having sickle cell trait. The NHS explains that a sickle cell trait carrier does not have the disease and cannot develop it, but could pass it on to their children. It also notes that you can have a blood test at any time to find out whether you are a carrier, and that sickle cell disease is more likely in people of African, Caribbean, Mediterranean, south and southeast Asian or Middle Eastern background.
The test
The Sickle Cell Screen looks for the presence of sickling haemoglobin in the blood. In England, sickle cell disease is usually found during pregnancy screening or through the newborn blood spot (heel prick) test, so adults who were born in England may already have been tested as babies. People born elsewhere, or who are unsure, sometimes choose to check.
Thalassaemia and haemoglobin electrophoresis
What thalassaemia is
The NHS describes thalassaemia as a group of inherited conditions that affect haemoglobin. It mainly affects people of Mediterranean, south Asian, southeast Asian and Middle Eastern origin. Thalassaemias are among the most common inherited conditions in the world (Kattamis et al., 2022). As with sickle cell, a person can be a carrier, also called having thalassaemia trait. The NHS explains that being a beta thalassaemia carrier will not generally cause health problems, but if both parents carry the gene for beta thalassaemia major, there is a 1 in 4 chance for each child to be born with the condition.
The test
Haemoglobin Electrophoresis separates the different types of haemoglobin in the blood. LML lists it as a thalassaemia screen and reports haemoglobin A2 and haemoglobin F among its results. It can also show other haemoglobin variants. LML notes that results usually come 1 day after the sample arrives, but may take longer if an unusual result needs confirmation.
Why a blood count matters too
Carriers of thalassaemia often have smaller red blood cells on a Full Blood Count, a pattern that can look similar to low iron (Kattamis et al., 2022). A professional may look at the blood count, iron markers and haemoglobin electrophoresis together to tell these apart.
Screening in the UK
England has a national NHS sickle cell and thalassaemia screening programme. The NHS explains that pregnant women are offered screening, ideally before 10 weeks for sickle cell, and the programme publishes a detailed handbook for laboratories. If you are pregnant, that NHS pathway comes first. Private testing is more often used before a pregnancy, by couples who want to know their carrier status early in their planning, or by adults who were never tested.
