Blood groups and transfusions

Molecules on the surface of red blood cells, usually proteins, glycoproteins, or glycolipids, that can be recognised by antibodies.

Antibodies are immunoglobulins produced in response to specific antigens

Clumping of red blood cells when antibodies bind to antigens on their surfaces and cross-link the cells.

They develop following exposure to environmental antigens, such as those from bacteria, that resemble red cell blood group antigens.

They develop after exposure to foreign red cell antigens, usually through transfusion or pregnancy, which stimulates an immune response.

A and B antigens; group O red cells lack both A and B antigens.

Anti-A and anti-B antibodies, depending on the individual's ABO blood group.

Anti-B antibodies.

A and B; both are expressed in people with blood group AB.

The observable blood group characteristics determined by the antigen on the blood cell surface membrane

The combination of inherited alleles that determines a person's blood group antigen expression.

Recipient anti-A or anti-B antibodies can bind incompatible donor red cells, causing agglutination and potentially severe acute intravascular haemolysis.

Group O negative for routine red cell transfusion when ABO and RhD compatibility are considered; other blood group antigens must also be considered.

Group AB positive, because these individuals generally lack anti-A and anti-B antibodies and are RhD positive; compatibility testing is still required.

A blood group system consisting of red cell membrane proteins, especially the D, C, c, E, and e antigens.

The presence of the RHD gene usually results in expression of the D antigen and an RhD-positive phenotype; absence or certain variants of the gene can result in an RhD-negative phenotype.

RhD positive, although prevalence varies between populations.

An RhD-negative pregnant person can become sensitised to RhD-positive fetal red cells and produce anti-D IgG, which can cross the placenta and cause haemolytic disease of the fetus and newborn in a current or subsequent pregnancy.

Anti-D immunoglobulin is given to eligible unsensitised RhD-negative pregnant people to prevent sensitisation to fetal RhD-positive red cells.

Usually around 28 weeks, either as a single-dose or two-dose regimen depending on the local protocol; it may also be needed after sensitising events and after birth if the baby is RhD positive.

Exposure can sensitise the recipient to the D antigen, leading to anti-D antibody formation and an increased risk of haemolytic transfusion reactions with subsequent exposure.

Plasma, red blood cells, white blood cells, and platelets.

Decision and consent → request → pre-transfusion sample collection and identification → sample receipt → compatibility testing → component selection and issue → collection and bedside identity checks → prescription/authorisation → administration, monitoring, and documentation.

Collection of a correctly identified patient blood sample, labelled at the bedside according to local procedures, for blood group testing and compatibility testing.

A potentially life-threatening reaction in which transfused red blood cells are rapidly destroyed, commonly due to ABO incompatibility and complement-mediated intravascular haemolysis.

Fever or chills, restlessness, chest or loinack pain, pain at the infusion site, breathlessness, nausea, and a feeling of impending doom; symptoms can vary.

Fever, tachycardia, hypotension, haemoglobinuria, and abnormal bleeding or disseminated intravascular coagulation; renal impairment may develop.

Shock, acute kidney injury, disseminated intravascular coagulation, multi-organ failure, and death.

Stop the transfusion immediately, assess and stabilise the patient, maintain IV access with compatible fluids using new tubing, urgently notify the clinical team and transfusion laboratory, and follow the local transfusion-reaction protocol.

An immune-mediated reaction in which transfused red cells are destroyed, usually extravascularly, several days to weeks after transfusion, commonly around 5–14 days later.