Crossmatching & Transfusion Reactions

• Patient identification is the most crucial step in compatibility testing and a common type of error
• Serum is the preferred specimen for compatibility testing.

  • Hemolysis should be avoided
• Plasma is not used in compatibility testing because it may cause small fibrin clots to form which may be difficult to distinguish from true agglutination.

  • It may also inactivate complement so that antibodies may not be detected.
• The freshest sample possible should be used for compatibility testing.

  • Specimens must be less than 3 days old if the patient has been transfused or pregnant within the past 3 months.
• Sample storage in compatibility testing

  • The AABB requires that patient samples must be stored between 1-6 °C for at least 7 days after transfusion
• ABO grouping is the most critical pretransfusion serologic test in compatibility testing
• If the patient’s ABO group cannot be satisfactorily determined and immediate transfusion is essential, group O packed red cells should be utilized.
• If Rh type of the recipient cannot be determined and transfusion is essential, Rh-negative blood should be given
• Crossmatching

  • Major X-match = Donor’s cells + Recipient’s serum
  • Minor X-match = Donor’s serum + Recipient’s cells
• The purpose of crossmatching is to final check the ABO compatibility between patient and donor to prevent transfusion reaction.

  • It detects the presence of antibody in patient’s serum that will react to donor’s RBC that is not detected in antibody screen.
• 3 phases of crossmatching

  • Immediate Spin in saline at room temp
  • detects IgM
  • Thermophase or 37°C incubation for 30 minutes with enhancement medium such as albumin, LISS, PEG
  • detects IgG
  • AHG Phase after washing incubated cells with saline
• In phases of crossmatching, Check cells or Coombs control cells (IgG sensitized cells) should be added to tubes that demonstrate no agglutination
• For results to be considered valid in crossmatching, agglutination must occur.
• A compatible crossmatch is indicated by absence of agglutination and/or hemolysis at any stage of the crossmatch.

  • The absence of agglutination indicates that the patient has no demonstrable antibodies with specificity for any antigen on donor’s RBC.
• A) ABO/Rh typing

  B) + DAT

  C) Low incidence Ab

  
• A) Alloantibody

  
• A) Autoantibody

  B) Roleaux

  
• Blood substitutes are substances that is able to carry oxygen in the absence of intact red cells
• Stroma-free Hemoglobin solutions or Hemoglobin-based Oxygen Carriers

  
• Perfluorochemicals are excellent gas (O2 and CO2) solvents
• Transfusion therapy or lesion of storage
• Autologous transfusion is a donation of blood by patients for transfusion to themselves in the future
• Emergency transfusion is given to patients who are bleeding rapidly and uncontrollable.

  • Group O negative units should be used especially if the patient is a woman of childbearing years
• Massive transfusion is defined as the replacement of one or more blood volume/s within 24 hours or about 10 units of blood in an adult
• Premature infants frequently require transfusion of small amounts of blood to replace blood drawn for laboratory tests, called Neonatal transfusion

  • Blood units less than 5 days old are preferred to lessen the risk of hyperkalemia and to maximize the 2,3 DPG levels
• Acute/Immediate hemolytic transfusion reaction is the most severe and may be life threatening due to ABO incompatibilities

  • S/S: fever, chills, hemoglobinuria, dyspnea, hypotension
  • Most severe cases may results to DIC and Renal Failure
• Acute/Immediate hemolytic transfusion reaction

  • The associated hemolysis is intravascular
  • Mediators: IgM Abs (usually to ABO antigens), complement
• Febrile nonhemolytic transfusion reaction increases temperature of greater than 1°C after transfusion; mild immunologic reactions that are caused by the interaction of recipient antibodies against HLS Antigens on Donor’s WBC and platelets

  • Most common S/S: fever and chills
  • Management/prevention: use of leukocyte filters during transfusion; Antipyretic
• Allergic transfusion reaction is the second most common type of transfusion reactions

  • IgE mediated
  • S/S: Urticaria, Erytheme, Hives, Itching, Anaphylaxix
  • Management/Prevention: Administration of Antihistamines before the transfusion
• Anaphylactic transfusion reaction

  • Mediator: plasma proteins, antibodies to IgA
  • M/P: transfusion of IgA-deficient compounds
• In Noncardiogenic pulmonary edema, most consistent finding is Anti-leukocyte Abs in donor or patient plasma
• Good example of iatrogenic transfusion reaction is transfusion associated circulatory overload

  • Common in patients with cardiac and pulmonary disease
  • May lead to congestive heart failure and pulmonary edema
• Delayed hemolytic transfusion reaction is characterized by the accelerated destruction of transfused RBCs

  • most commonly associated with a secondary response
• Delayed hemolytic transfusion

  • The associated hemolysis is generally Extravascular
  • Mediators: IgG Abs to Rh, MNS, Kell, Kidd and Duffy antigens
• Transfusion associated Graft vs. Host disease occurs when immunologically competent lymphocytes are transfused into an immunocompromised host.

  • S/S: Fever, liver problems, rash and diarrhea
  • M/P: transfusion of irradiated blood components
• Graft vs. host disease occurs when white blood cell in transfused blood attack the tissues of a transfusion recipient who has a severely weakened immune
• To prevent WBC from causing GVHD, donated blood can be treated with radiation before transfusion
• Post-transfusion purpura is a rare transfusion reaction usually seen in older female patients who have been sensitized to platelet antigens, either by previous pregnancy or transfusion.

  • Characterized by severe thrombocytopenia one week after transfusion due to antibody to platelet specific antigen
• Transfusion-induced Hemosiderosis is the iron deposition in vital organs seen in patients who are thalassemics and with chronic transfusions
• Transfusion of stored blood has not been shown to transmit syphilis because spirochetes do not survive at ref temp for 72 hours