Blood Transfusion

Blood TransfusionLaboratory testBlood products

By: Izatty Lim (0308188)

Essential that all blood is tested before transfusion:

Ensure that transfused red cells are compatible with antibodies in the recipients plasma

Avoid stimulating the production of new red cell antibodies in the recipient, particularly anti-RhD.

LAB TEST

All pre-transfusion test procedures should provide the following information about both the units of blood and the patient:

ABO group RhD type Presence of red cell antibodies that could cause haemolysis in the recipientInfective screeningLAB TEST

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1. ABO Blood Group

These antibodies are usually of IgM and IgG class and are normally able to haemolyse (destroy) transfused red cells.

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Blood grouping methods: Tube methodGel method

Forward grouping: using known anti-A, Anti-B, Anti-AB antisera Reverse grouping: using known A1 cells, B cells and O cells. Infants less than 4 months old do not require reverse grouping.

In a life threatening situation, group O packed red cells may be issued.ABO Blood Group

Tube method:principle of agglutination. Normal red blood cells, possessing antigens, will agglutinate in the presence of antibodies directed toward those antigens. Commercial antisera are used to test patient and donor cells. Patient plasma/serum is then tested against reagent A1and B red cells. The ABO reaction should be reciprocal and does not require red cell stimulation.

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A single unit of RhD positive red cells transfused to an RhD negative person will usually provoke production of anti-RhD antibody.

This can cause: Haemolytic disease of the newborn in a subsequent pregnancy Rapid destruction of a later transfusion of RhD positive red cells.2. RhD

Rh D grouping: using Monoclonal IgM/IgG blend antisera by one of the following methodsTube methodGel method

recommended that Rh D should be tested in duplicate with two IgM/IgG blend monoclonal anti-D blood-grouping reagents, with one which should not detect D VI .

Rh D negative patients should be phenotyped for C, c, E & e antigens.RhD

Weakened expression of the RhD antigen The collective term Du is widely used to describe red cells which have a weaker expression of the D antigen than normal. The term weak D denotes individuals with a reduced number of complete D antigen sites per red cell. The term partial D denotes individuals with missing D antigen epitopes. DVI is a partial D category which misses most D epitopes. Blend reagent will detect most examples of partial and weak D red cells by direct agglutination, but will not detect DVI cells. This reagent will detect DVI and partial D cells in the IAT phase. 7

Detecting clinically significant red cell antibodies reactive by hemolysis and/or haemagglutination at room temperature, 37C. Include a 37C incubation phase and an indirect antiglobulin test. 3. Antibody Screening

Reagent red cells shall consist of at least two group O red cells, NOT POOLED, and should express the following antigens: C, c, D, E, e, M, N, S, s, K, k, Fy a , Fy b , Jk a , Jk b . Where possible, one cell should be of the R1R1 phenotype (CDe phenotype) and the other of R2R2 phenotype (cDE phenotype). Additional antigens may be included to reflect the antigenic profile of the local population8

If screening test is positive and/or incompatible cross-match detected, antibody identification should be performed using a reagent red cell panel that covers all the significant antigens. should be able to demonstrate the presence of antibody

Provide blood that is negative for the corresponding antigenlead to more samples needed and a considerable delaypotential risk of adverse reactions must be balanced with the risk of delaying the transfusion

4. Antibody Identification

Rh system: Rh C, c, E, e Kidd Kell Duffy LewisOTHER RED CELL ANTIGENS AND ANTIBODIES

Crossmatchpatient's serum is tested directly for compatibility with the red cells of the units of blood to be transfused after ABO and Rh D determination with or without antibody screening carried out at room temperature, 37C and with antihuman globulin (AHG/IAT) phase.

If clinically significant antibodies are present or where there is history of clinically significant antibodies, antigen negative blood should be cross matched until AHG/IAT phase.5. COMPATIBILITY TESTING

Samples from patient to whom the crossmatched blood is transfused should be retained for at least 7 days post transfusion for the purpose of investigation of any reported transfusion reactions. 10.6.5 Once a transfusion has commenced, new sample is required for further transfusion. Sample should always accompanied by request form .However, if the second crossmatch gives an incompatible result eventhough specific antigen-negative group is given and similar to the previous transfusion, a re-investigation for antibody must be performed. 10.6.6 Units that have been crossmatched but not transfused within 48 hours shall be subjected to pretransfusion testing against a new sample from the patient. 11

Screening of all blood donations should be mandatory for the following infections and using the following markers:HIV-1 and HIV-2: screening for either a combination of HIV antigen-antibody or HIV antibodies

Hepatitis B: screening for hepatitis B surface antigen (HBsAg)

Hepatitis C: screening for either a combination of HCV antigenantibody or HCV antibodies

Syphilis (Treponema pallidum): screening for specific treponemal antibodies.6. Infective Screening

Screening of donations for other infections, such as those causing malaria or Chagas disease, should be based on local epidemiological evidence. 4 Screening should be performed using highly sensitive and specific assays that have been specifically evaluated and validated for blood screening. 5 Quality-assured screening of all donations using serology should be in place before additional technologies such as nucleic acid testing are considered. 6 Only blood and blood components from donations that are nonreactive in all screening tests for all markers should be released for clinical or manufacturing use. 7 All screen reactive units should be clearly marked, removed from the quarantined stock and stored separately and securely until they are disposed of safely or kept for quality assurance or research purposes, in accordance with national policies. 12

Selection of red cells for transfusion Selection Of Suitable Red Cell Units For Transfusion In The Presence Of Antibodies

Recommended ABO group for plasma products (FFP, cryoprecipitate and cryosupernatant)

Platelet concentrates in order of preference should be:patients own ABO group ABO antigen compatible (but plasma incompatible) ABO antigen incompatible Selection of non red cell products

Any therapeutic substance prepared from human blood

Whole bloodUnseparated blood collected into an approved container containing an anticoagulant-preservative solution

Blood componentA constituent of blood, separated from whole blood

Plasma derivativeHuman plasma proteins prepared under pharmaceutical manufacturing conditions

BLOOD PRODUCTS

Up to 510 ml total volume (volume may vary in accordance with local policies)450 ml donor blood 63 ml anticoagulant-preservative solution Haemoglobin approximately 12 g/ml Haematocrit 35%45% No functional platelets No labile coagulation factors (V and VIII)1. Whole BloodIndicationRed cell replacement in acute blood loss with hypovolaemiaExchange transfusionPatients needing red cell transfusions where red cell concentrates or suspensions are not available

RED CELL CONCENTRATE (Packed red cells, plasma-reduced blood)150200 ml red cells from which most of the plasma has been removed Haemoglobin approximately 20 g/100 ml (not less than 45 g per unit) Haematocrit 55%75%2. Blood ComponentsIndicationReplacement of red cells in anaemic patientsUse with crystalloid replacement fluids or colloid solution in acute blood loss

RED CELL SUSPENSION150200 ml red cells with minimal residual plasma to which 100 ml normal saline, adenine, glucose, mannitol solution (SAG-M) or an equivalent red cell nutrient solution has been added Haemoglobin approximately 15 g/100 ml (not less than 45 g per unit) Haematocrit 50%70%Blood ComponentsIndicationReplacement of red cells in anaemic patientsUse with crystalloid replacement fluids or colloid solution in acute blood loss

LEUCOCYTE-DEPLETED RED CELLSA red cell suspension or concentrate containing