Blood groups and blood transfusions

Give detail on haemolytic transfusion reactions How they happen What occurs in the body A secondary pathology that can occur Management of this

*Haemolytic transfusion reactions* • This can be immediate or delayed, with more serious reactions being caused by transfusion of ABO-incompatible red cells that bind on to the patient's anti-A/anti-B antibodies and activate the complement system. • This leads to intravascular haemolysis (destruction of the transfused red cells) and releases inflammatory cytokines that can lead to renal failure, shock and disseminated intravascular coagulation [DIC] (blood is unable to clot properly) • In the delayed reaction, pre-transfusion levels of antibodies that were too low to be detected in a cross-match means that a patient may be re-immunised with incompatible red cells which leads to a delayed transfusion with increased clearance of red blood cells. • Acute presentation: chills, fever, hypotension, haemoglobinuria, renal failure, back pain, DIC • Delayed presentation: anaemia (due to a falling Hb count, jaundice (rapid or mild) *Management of patients with haemolytic transfusion reactions* • Main thing is to maintain blood pressure and renal perfusion • Given IV dextran, plasma/saline and often furosemide • To alleviate shock: hydrocortisone 100mg IV, antihistamines (if severe shock give nebulised adrenaline) • Severely affected patients: give further compatible transfusion • Acute renal failure: use dialysis if necessary

What testing do you do before cross matching? What is cross matching? What is the purpose? When is it done? How long does it take?

1. Blood grouping of the recipient (ABO and Rh) 2. Screening for abnormal recipient antibodies o Indirect antiglobulin test: The recipient's serum is tested against a standard pool of red cells to detect antibodies to blood group antigens other than those of ABO and Rh systems o Screening cells and cell panels (To identify the antigen against which the antibody is reacting) 3. Each unit of donor blood to be transfused is then tested 'cross-matched' against the patients serum to identify atypical antibodies in the patient. This then makes that unit of donor blood unsuitable for other patients. This may not need to be done if no antibodies were found in the initial test. This last step 'Cross matching' is with the ACTUAL unit of blood with your blood - final check do this like 20 mins before you give the blood. Safety check. • This can take under an hour but can take longer if antibodies are present • Most hospitals will only hold cross matched blood for 24 hours

Give some information labs need when requesting transfusions/blood?

1. Patient's ID and gender 2. Diagnosis, and any other relevant clinical information plus a well-written reason for transfusion (not just anaemia or pre-op written) as lab staff can then choose appropriate components. 3. Time, location and urgency of transfusion 4. Information (if applicable) on previous reactions, blood group antibodies or pregnancies 5. Type, dose and volume of blood component required 6. Any special requirements e.g. irradiation, CMV -ve blood

Blood group: AB Give possible phenotypes Give relative prevalence Give antibodies that will be present in plasma

AB 4% No antibodies (Universal receiver as they don't possess ABO antibodies)

Blood group: A Give possible phenotypes Give relative prevalence Give antibodies that will be present in plasma

AO and AA 42% Anti-B

Blood group: B Give possible phenotypes Give relative prevalence Give antibodies that will be present in plasma

BO or BB 10& Anti-A

Name other blood derived products?

Clotting factor concentrates White cells

Give some common and less common side effects of blood transfusiosns

Common symptoms include: • a raised, red, itchy skin rash (urticaria) • swelling of the hands, arms, feet, ankles and legs (oedema) • dizziness • headaches Less common symptoms include: • high temperature (fever) of or above 38C (100.4F) • chills • shivering • shortness of breath • swelling of the lips or eyelids

Give a technique use before cross matching to detect antibodies

Coomb's test: • Antihuman globulin (AHG) is produced in animals following the injection of human globulin. Monoclonal preparations are now available • There are two types of coombs' test, direct and indirect • Direct antiglobulin test is used for detecting antibody or compliment already on the red cell surface where sensitisation has occurred in vivo • The AHG reagent is added to washed red cells and agglutination is a positive test • A positive test occurs in haemolytic disease of a newborne and others • Indirect antiglobulin test is used to detect antibodies that have coated the red cells in vitro • This test is used as part of the routine antibody screen of the recipients serum prior to transfusion

Anti-A and Anti-B are usually what sort of antibody?

IgM Cannot cross the placenta and are easy to test for. These are found in the serum of those lacking the corresponding antigen

Blood group: O Give possible phenotypes Give relative prevalence Give antibodies that will be present in plasma

OO 44% Anti-A and Anti-B (Universal donor)

Give a technique used to detect IgM antibodies?

Saline angulations

Give some principles labs employ that improve transfusion safety and reduce the risk of a reaction

¥ Only accept correctly labelled samples ¥ Label the blood sample at the bedside ¥ Compare results with previous blood bank records ¥ Ask for a second sample if there is no previous blood group to compare with ¥ Use a "closed system" in lab - no manual handling/ transcription ¥ Use electronic patient identification

How much PRCs and platelets do you give someone, on the whole?

• 1 unit of blood increases the Hb by 10/L in a 70Kg man. Obviously this varies in the size of the person. Be careful • On the whole 2 bags of platelets isn't any better than one, so often just prescribe 1

What is the danger, therefore, in producing these antibodies?

• 70% of Rh- people will produce antibodies after receiving Rh+ blood and therefore, if they are transfused with Rh+ blood in the future they will develop a transfusion reaction • As well as RhD, those with C, c and E antigens may have a haemolytic reaction after transfusion. This is usually delayed and not immediate.

What's the universal plasma donor?

• AB plasma is the universal donor With plasma, just worried about antibodies

What type of antibodies are produced against ABO?

• Antibodies to ABO antigens occur naturally and are IgM and complete. (Easier to test)

What is apheresis?

• Apheresis allows the removal of one specific component of blood such as platelets • Blood withdrawn is separated and the selected component taken out • The rest of the blood is then returned to the donor • This usually takes 1-2 hours • Because only one component is taken, a lot more of it can be taken

What do you do to the blood before it goes into the body?

• Blood is warmed and then rapidly transfused to prevent vasoconstriction which would reduce the rate of transfusion

Why do people develop anti-A and anti-B when they're never exposed to that blood?

• By 6 months of age the baby will have been exposed to Anti-A and Anti-B like antigens via the enter bacteria in intestinal bacteria and food substances • IgM antibodies develop against A and or B antigens (Unless, of course, these are present on the RBCs - self tolerance) • Therefore, because of this people who are group OO will have both anti-A and anti-B antibodies, whereas those with both AB will have none.

Give details on the compatibility of blood groups with plasma?

• Compatibility with plasma is the opposite of red cells • For example, O plasma contains anti-A and anti-B antibodies so it should only be given to O recipients • Therefore, AB is the best donor?

FFP What is it? What is it's indications? Where is it obtained from?

• FFP contains albumin, immunoglobulins and all the clotting factors • It is superseded in the majority of uses by manufactured coagulation concentrates - for example in haemophilia *Indications include:* • Multiple clotting factor deficiencies (Eg. In severe liver disease, warfarin overdose, massive transfusion and thrombotic thrombocytopenic purpura where it is used in plasma exchange • Specific coagulation factor replacement where no concentrate is available (Factor V deficiency) • Plasma loss (albumin solution is used in many cases - for example, burns) • Liver disease • DIC • Sourced from UK • Stored at -30degrees • ABO compatible • Defrost and use within 24 hours

What is the most important thing when testing blood/cross matching etc..?

• First, correctly identify the patient and label patient samples correctly • This is to prevent potentially fatal reactions

Give a list of the different types of transfusion reactions

• Haemolytic o due to an antigen-antibody reaction as a result of an incompatible transfusion, resulting in severe or fatal intravascular haemolysis. • Non-haemolytic o due to damaged blood products that release high levels of cytokines, leading to fever and rigor. Usually benign. • Allergic reactions (IgE mediated) o leading to rashes and itching. Benign. • Anaphylactic reactions (IgA mediated) in certain patients. Potentially, but rarely, fatal. o Need to have IV adrenalin on standby o The patient will be wheezy • Transfusion of antileucocyte antibodies o leading to transfusion-related acute lung injury (TRALI). Can be fatal. • Due to volume overload o leading to acute pulmonary oedema. Outcome depends on the other conditions. • Transfer of bacteria o leading to endotoxaemia (as a result of free bacterial toxins) and septicaemia. Potentially fatal.

So there's natural antibodies one produces like anti A when they have group B blood but you can also develop antibodies. What type of antibody are developed antibodies? When do you develop them Can they cross the placenta?

• However immune antibodies also develop in response to o A blood transfusion o Foetal red cells across the placenta in pregnancy • The antigens are of red cells that the subject doesn't possess • These antibodies are commonly IgG • Note that only IgG antibodies are capable of passage across the placenta

What type of antibodies are produced against the other RBC proteins/antigens that aren't ABO?

• However, antibodies to other red cell antigens appear only after sensitisation and are usually IgG and incomplete. (Harder to test for)

When do you use prothrombin complex concentrate?

• If you can't wait for warfarin patients to stop warfarin for 3 days then you give this which reverses the function

When can alloantibodies be produced?

• Individuals lacking a red cell antigen may make alloantibodies (Antibodies in one individual reacting to cells of another individual) if exposed to it by transfusion or transfer of foetal red cells across the placenta in pregnancy

Ethical and religious considerations in blood transfusions Particularly with Jehovahs

• Jehovah's witnesses decline blood transfusions- this isn't because of the perceived risks of blood transfusions rather it is due to a scriptural stand based on biblical texts. • It's worth noting that not all Jehovah's witnesses refuse blood transfusions and so it isn't wise to assume that they will never want it. • Certain groups of Jehovah's witnesses may accept transfusions of derivatives of primary blood components but not the blood cells themselves. • They frequently carry Advanced Decision Documents listing what they will/won't have transfusions wise and a copy of this should be in the patient record. • It's also worth having a talk with the patient to ensure they have made an informed decision after being educated about potential risks of their decision/other possible alternatives to transfusion- however it is ultimately up to them as to what they want to do.

If a person has had a group and save, then had a blood transfusion can you use the initial group and save?

• No you would need to do it again

When are antibodies to rhesus antigens produced? What type of antibodies are these?

• Now, anti-D antibodies are only produced when a Rh negative individual is exposed to Rh positive RBCs (Following transfusion or pregnancy). Anti-D is the only one that causes any real issues. • Rhesus antibodies RARELY occur naturally • All anti-D antibodies are IgG

What is graft vs host disease?

• Occurs when live lymphocytes are transfused in a patient with immunosuppression. • Presentation: pancytopenia, maculopapular rash, diarrhoea, hepatitis (1-4 weeks post transfusion). • Management: usually fatal, however can be prevented by irradiating blood products.

Once FFP (and actually most blood products!) has been taken out of the fridge, when can you use it?

• Once FFP is defrosted, usually use within 4 hours

Fertile women and blood

• Only give women O- or their actual blood as this may cause trouble with babies

Give the details of what blood is broken down into, and how many days it lasts. Note, the longer it lasts the cheaper it is, generally. Also, the lest steps involved the cheaper it is.

• Packed red cells (35 days) (£150/bag) • Platelets (7 days) (£300/bag) • Fresh frozen plasma (36 months) • Individual clotting factors • Cryoprecipitate • Albumin

Can the patient be a blood donor if they've had a blood transfusion?

• Patient can't be a blood donor • They're at increased risk of transfusion reactions because of those antibodies being produced

What is the patient consent process like with blood transfusions?

• Recommended that valid consent should be obtained and documented in the clinical record. • Patient should be given sources of information e.g. leaflets and this should be available in all hospitals. • In emergency treatment, needing consent mustn't delay/prevent need for urgent transfusion, unless the patient has a valid Advance Decision document. • Patients that need long term transfusion should have a modified form of consent that should include sections on annual review and re-consent.

How do you make 'Packed red cells' as you seldom give full blood.

• Red cells are separated from plasma and platelets and 'packed' with saline-adenine-glucose-mannitol (SAGM) solution. • These have a shelf life of 35 days

What makes blood groups on RBCs?

• Red cells have surface antigens on them which are glycoproteins or glycolipids • The red cell surfaces are covered with antigenic molecules. Over 200 are on the surface, yet only a few are clinically significant

Platelets How are they stored Shelf life Different ways of getting platelets Indications for platelets

• Stored at room temperature • Have a half life of 4-5 days • They can be obtained from a pool of 6-10 blood donors or from a single donor via apheresis *Indications for platelet transfusion is:* • Patients who are bleeding and who have a platelet count <50x109/L • Following massive transfusion resulting in dilutional thrombocytopenia • Patients with platelet dysfunction who are bleeding • Prophylactically in patients with thrombocytopenia who are undergoing surgery or who have bone marrow failure

When do patients have natural antibodies?

• The ABO blood group antigens naturally occur antibodies in the plasma of subjects who have not been transfused or been pregnant • The most important of these antibodies are anti-A and anti-B

Give the genetic principles of Rhesus alleles and

• The D antigen is coded for by the RhD gene. • The presence of the RhD allele results in the D antigen being present written as 'D' • The lack of RhD gene is written as 'd' • Rhesus positive individuals are either Dd or DD • Rhesus negative individuals have to be dd • 85% of Caucasians are Rh positive

How about you have someone on the ward, you could give them a transfusion but what 3 other things could you try first?

• The Safest transfusion is the one you don't have • Anaemia o Iron tablets, IV iron, Vit B12 and folic acid o Corticosteroids, erythropoietin and treating underlying cause • Thrombocytopenia o Platelets only if bleeding, corticosteroids o To maximise clotting avoid aspirin • Plasma o Don't use as a volume expander o Recombinant factors 8+9, fibrinogen concentrate and vitamin K

Name some other weird antibodies they can produce?

• The blood here is matched for ABO and RhD antigens • There are other antigens like Kell and Duffy which are not matched for • The more blood the patient receives, the more likely an alloantibody will have formed to a red cell antigen

Is the ABO genes/alleles dominant, recessive or codominant?

• The genes coding for A and B are co-dominant

What things must you consider when giving a blood transfusion?

• The size and weight of the patient. Too much blood and you can send them into heart failure. • Other things such as allergy, and previous transfusions

Genetically, explain what produces ABO and how they're different?

• The system consists of 3 alleles, AB and O which code for a sugar-residue transferase enzymes • ```the protein that defines the ABO antigens is a glycosyl-transferase that is encoded from a single gene for which there are three major alleles. o O gene doesn't make any difference to the protein o A and B gene o AB is referred to as H • The ABO gene has 3 alleles corresponding to the 3 antigens

When you have a Rh- mum and a Rh+ father then what is the risk?

• Then you can get transferred blood from baby to mum. • Antibodies from mum can cross plasma and can cause a damaged baby. • Every Rh- mum can get an injections of anti-D and also offer it again later on in pregnancy. If you suspect a women has had a bleed ie fall down stairs then you can offer more anti-D because this increases the risk of blood crossing the placenta.

What are the different types of rhesus antigens? Which is the strongest immunogen?

• These pesky antigens are stronger immunogens and the antibodies generated are clinically important • These are known as C,D,E. However the D antigen is the most clinically important. • When someone is "Rhesus positive" they are positive for the rhesus antigen D. • D antigen is the strongest immunogen

What is cryoprecipitate? What does it contain? When is it used?

• This is an insoluble precipitate formed when FFP is thawed at 4degrees o You get it from plasma, as an extra step. As a result it's more expensive • It contains factors 8,vWF, 13 and fibrinogen. • It is given to control bleeding associated with defects • It can be used in chronic renal failure, advanced liver failure and disseminated intravascular coagulation. • It's also valuable following massive blood transfusion • Basically you use it when you have a low fibrinogen level. It can also be useful for DIC

What is group and save? When is it used? How long is it used for? What about if they have a new transfusion?

• This is used when the blood is not required immediately, but may be needed in the near future • It involves testing the patients sample and storing it for 7 days • If, in that period the patient needs blood then it will be available in 15mins, after the final cross matching is done) • This is the basis of the '72 hour rule' where a new antibody may have been detected. 72 hours post transfusion... if you want to give another one you have to recheck, re cross match the patient

Give some indications for red cell transfusion

• Trauma • Surgery • Shock • Severe anaemia (Often associated with hemoglobinopathies) • Chemotherapy • Hb below 70 (Risk of cardiac problems) • Haemorrhage • Haemolytic anaemia • Sickle cell crisis - exchange transfusion

How much, typically, will every unit of blood increase the Hb by?

• Typically, every unit will increase the HB by 1 g/L

Give some factors that will make you decide the amount and speed of a blood transfusion?

• Typically, every unit will increase the HB by 1 g/L • If the patient is shocked, you need to restore circulating volume therefore the quicker the better give over 20-30 mins if bleeding • Give over 2-4 hours if stable • Be aware of a massive transfusion - as other products will be needed

Give a list and some details about them of some alternatives to blood, particularly when they decline on religious grounds

• Volume expanders o Used in an acute setting to help avoid shock • Growth factors, such as EPO. o These are not used in an acute setting, but work by stimulating the bone marrow to produce more RBCs • Intraoperative blood salvage o Blood lost during surgery is collected and reinforced into the patient • Autologous blood donation o This is where the patient donated their own blood that can be saved and infused back into the individual should they need it. o This has been used for fit patients having planned surgery. o Also used as "Blood doping" in cheating athletes • Synthetic blood substitutes - with little success

How do we protect from variant CJD?

• We deplete leukocytes from blood products to reduce the risk of infection

Give some general principles of the massive blood loss protocol in hospitals How to initiate What blood do you give? What other blood products could we give? What non-blood products can we give?

• When you give blood, give O- if you don't know the donor group and cross match at that point • If you recognise it's a massive blood loss hospitals have certain things in place that automatically provide FFP and platelets without asking • They require these, because although clotting factors and platelets will be normal at first - as soon as you start pumping RBCs into the patient the coagulation and platelets will drop down. • FFP is a good choice for replacement coagulation • Saline to by time - resuscitation • Prevent coagulopathy (Ie. Platelets or FFP). Remember transfusion will not stop bleeding, it will just by time • During emergency situations patients have often not had a cross-match sample taken • If a patient needs blood immediately, then a cross-match sample should be taken and O- blood given

Principles of transfusing blood based on ABO alone Universal donor/recipient

• When you transfuse blood it should be ABO compatible with the recipients blood • For example, if group A red cells are given to a group O recipient anti-A antibodies in the recipients serum will destroy the donors cells • Ideally ABO-identical blood is used. However, if this is not possible then group O can be used as it contains no A or B antigens to react with the antibodies. Group O = universal donor • However, the serum of people with group O will contain some anti-A and anti-B antibodies and so it's always desirable to match ABO specifically. • Conversely, AB individuals are the universal recipients as they do possess anti-ABO antibodies.