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Introduction ⬇

Pretransfusion testing of blood recipient and donor blood

  1. All donated blood, as it is processed, must undergo several measurements. These include tests for the following factors:

    1. ABO groups

    2. Rh type

    3. Antibody screen

    4. HBsAg

    5. HBcAg

    6. HCV (anti-HCV)

    7. Syphilis (VDRL)

    8. HIV-1 and HIV-2

    9. HTLV-I and HTLV-II

    10. HIV antigen (HIV-1-Ag)

    11. NAT (narrow window of infection for HIV and HCV)

    12. Chagas disease—caused by Trypanosoma cruzi

  2. Required testing for whole blood or red blood cell recipients includes the following:

    1. ABO group

    2. Rh type

    3. Antibody screen

    4. Cross-match for compatibility between donor’s cells and recipient’s serum

Type and screen, when ordered preoperatively, identify ABO and Rh type group and are used for cases that usually do not require transfusion. Even though no cross-match is needed for plasma administration, compatible ABO typing should be done. Routinely, no cross-match is needed for platelet administration; compatible ABO and Rh types should be given when possible. If a patient becomes refractory, HLA-matched platelets may be administered. Granulocytes should be tested for HLA compatibility. As a result of previous transfusions or pregnancy, some patients develop antibodies against these antigens and, if given platelets that have these antigens, may have a transfusion reaction. Pretransfusion testing for neonates (younger than 4 months) requires determination of ABO group, Rh type, and an antibody screen. The antibody screen may be performed on a specimen obtained from the infant or the mother. If the antibody screen is negative, group O Rh compatible pediatric red blood cells may be used without further cross-matching for the remainder of the neonatal period. If the antibody screen is positive, the antibody is identified, and antigen-negative blood will be cross-matched and provided for transfusion. All infants requiring plasma transfusions will receive group AB pediatric fresh-frozen plasma.

A type and screen consists of an ABO group, Rh type, and antibody screen and can be ordered when the need for cross-matched products is unlikely but may be required in an emergency situation. If the patient does have a clinically significant unexpected antibody, at least 2 U of antigen-negative blood will be made available for that patient before surgery. A positive antibody screen will automatically initiate antibody identification to determine the specificity of the antibody detected. If the antibody identified is determined to be clinically significant, antigen-negative blood is required for transfusion.

  1. Autologous donations are blood products donated by patients for their own use (i.e., blood donor and recipient are the same person). Many patients opt to donate their own blood before scheduled surgery because of the concern regarding transfusion-transmitted diseases. The following are some general guidelines for autologous blood donation:

    1. There is no age limit if donor is healthy.

    2. There are no weight requirements. The volume of blood collected must comply with established weight provisions.

    3. Pregnant women can donate.

    4. Hematocrit should be >33% (or >0.33). If <33% (or <0.33), the patient’s healthcare provider must approve the phlebotomy, usually in consultation with the blood bank medical director.

    5. Normally, phlebotomy can be done at 3-day intervals; the final phlebotomy can be done no sooner than 72 hours before the time of the scheduled surgery. Two-unit collections using an automated red cell pheresis machine may also be an option. Iron supplements may be prescribed to maintain adequate hemoglobin levels.

    6. Autologous blood is not “crossed over” into the general (allogeneic) blood supply. It is discarded after its expiration date.

  2. Allogeneic donations are blood products donated by one individual for use by other individuals (i.e., blood donor and blood recipient are not the same person).

  3. Direct donations are those in which recipients choose those who donate blood for their transfusions. Laws in several states declare that this request must be honored in nonemergency situations. Standards and testing procedures must be identical to those required for an allogeneic blood donor. (Autologous donors do not need to adhere to the same criteria as do allogeneic blood donors.) Directed donor units can be “crossed over” into the general (allogeneic) blood supply. Each establishment must have a policy describing when this can occur.

  4. CMV testing is done for patients at risk for transfusion-associated CMV infections. These types of CMV infections include pneumonitis, hepatitis, retinitis, and disseminated infection. They generally occur in immunosuppressed patients, such as premature infants weighing <1200 g at birth, bone marrow and organ transplant recipients, and certain immunocompromised oncology patients. Therefore, to prevent these infections, CMV antibody testing is done. Patients at risk should receive CMV-seronegative blood and blood products. CMV in blood is associated with leukocytes. Leukocyte reduction using highly efficient leukocyte-reduction filters also appears to be an effective way of reducing CMV infection.

  5. Irradiation of blood products is sometimes done before transfusion for certain immunosuppressed patients. Graft versus host disease (GVHD) is a rare complication that follows transfusion in severely immunosuppressed patients. GVHD occurs if donor lymphocytes from blood or blood products engraft and multiply in a severely immunodeficient recipient. The engrafted lymphocytes react against host (recipient) tissues. Clinical symptoms include skin rash, fever, diarrhea, hepatitis, bone marrow suppression, and infection, which frequently leads to death. GVHD can be prevented by irradiating blood products with a maximum dose (cesium-137) of 2.5 cGy in the center of the container and a minimum dose of 1.5 cGy delivered to all other parts of the component. This practice renders the T lymphocytes in a unit of blood incapable of replication without affecting platelets or granulocytes. Irradiation does affect the red cell membrane, causing it to “leak” potassium. All irradiated red cells are given a 28-days “outdate” or may keep their original outdate of less than 28 days.

  6. Leukocyte reduction of blood products: Leukocytes in blood products have long been known to be associated with nonhemolytic febrile transfusion reactions, possibly owing more to cytokines produced by the leukocytes than the leukocytes themselves. Leukocyte reduction may reduce the number of these reactions. It may also decrease the possibility of alloimmunization to the HLA antigens on the leukocytes. Removing leukocytes may effectively reduce the danger of transfusion-transmitted CMV infection.

Procedure ⬆ ⬇

  1. Using a 10-mL plain, red-topped tube, collect a venous blood sample for hospital pretransfusion testing.

  2. Label with the following information:

    1. Patient’s full first and last names

    2. Patient’s healthcare record number

    3. Date and time of specimen collection

    4. Initials (if collected by laboratory personnel) or signature (if collected by nonlaboratory personnel) of phlebotomist

    5. Possibly a unique blood bank number (found on special blood bank identification band)

  3. Attach a special blood bank band, at the recipient’s bedside, at the time of specimen collection. The blood bank band must remain attached to the patient’s wrist throughout the transfusion period. The same band may be used throughout one hospital admission as long as the information printed on the band is legible and the band is still securely attached to the patient’s 
wrist.

  4. A new blood group and antibody screen is required every 72 hours.

Interventions ⬆

Pretest Patient Care

  1. Before transfusion, there is a requirement for healthcare providers to document that all the alternatives to transfusion, risks for transfusion, and transfusion issues were explained to the patient.

  2. Discuss with the patient the need for blood or blood components, risks (infection, disease, reactions, alloimmunization), benefits (treatment for active bleeding, anemia, clotting disorders), and alternatives to random allogeneic donation (predeposit autologous donation, intraoperative salvage, directed donor donation). Allow sufficient time for patient to ask questions, resolve concerns, and give voluntary consent.

  3. The healthcare provider must document in the health record that the earlier discussions took place and provide documentation, including informed consent (see Appendix F). There must be documentation in the chart before the patient receives the transfusion.

  4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.