Sometimes DHTR cannot be prevented if the patient's antibody is too weak to be detectable. However, there are several things a transfusion service can do to try to prevent them. The protocols below are examples. Individuals should always adhere to the policies developed in their institutions.

  1. Records

    Checking records for prior history of transfusion and presence of known antibodies. For patients; with clinically significant antibodies, antigen-negative donor units must be crossmatched even if the antibody is currently undetectable.

  2. Communication.

    It is important for nurses and physicians to relay any information about known antibodies to the transfusion service, since antibodies may have been identified at a different site.

  3. Sensitive antibody screen cells

    At least one screen cell should be homozygous for any antigens that show dosage.

  4. Sensitive antibody detection methods

    LISS, PEG, gel, and solid phase adherence assays are all sensitive methods. If the less-sensitive saline method is used, a larger plasma to cell ratio (e.g., 4 or 6 drops of plasma to 1 drop of 3-5% cells) and longer incubation times (e.g., 45-60 minutes) increase the sensitivity of the test.

  5. Fresh patient specimens(less than 3 days)

    Fresh samples will help detect a 2° immune response in a patient with a pre-existing weak antibody, particularly in a patient who is being transfused regularly.
  6. Periodic re-identification of antibodies

    If a patient with a known antibody is being transfused regularly, re-identification of antibodies should be done periodically so that any new antibodies can be detected. Laboratories often use an abbreviated panel to detect the presence of new antibodies that may have formed.
  7. IAT crossmatch for patients with antibodies

    If a patient has a previously identified clinically significant antibody, antigen-negative red cells must be selected for crossmatch and the crossmatch must be performed by the antiglobulin (IAT) method.

  8. Antigen typing of crossmatch compatible donors

    If the antibody screen is positive, seemingly compatible donors should NOT be issued (except for life-threatening emergencies) until the antibody is identified and the donors are antigen typed and found to be antigen-negative. In emergencies, the patient's physician must be made aware of the risk of transfusing  crossmatch-compatible blood before the antibody was identified.

Discussion Question

  1. In this case were best practices followed?