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    ST. PAUL'S HOSPITAL

    Hospital Transfusion Service Testing

October 19, 2000

Mr F.S. attended the pre-assessment clinic at St. Paul’s Hospital. His preoperative hemoglobin was 140 g/L. Laboratory SOP states that type and screen samples are held for one month if there is no history of transfusion in the prior three months.

See initial type and screen results

October 24, 2000

• Four units of red blood cells (RBC) were requested and, after an electronic crossmatch, all four RBC units were transfused in the Operating Room.

• Post-operatively Mr. F.S.'s hemoglobin was 106 g/L and slowly dropped to 88 g/L on the 7^th day post op. No additional type and screen requests were received.

• Mr. F.S. was discharged from St. Paul's Hospital on 31 October, 2000.

     MSA General Hospital

November 4, 2000

Mr. F.S. was sent to the MSA hospital laboratory for blood work. His hemoglobin was 78 g/L and an increased WBC and platelet counts. Plasma urea and creatinine results were normal. History check revealed previous transfusion at MSA Hospital on October 16, 1997.

Subsequently, a 4-unit crossmatch was ordered. See these workups:

• Type and Screen and DAT
• Antibody Identification (Panel 1)
• Antibody Identification (Panel 2)
• Summary of Panels, Selected Cells and Self Test
• Patient Phenotyping (Pretransfusion Specimen)

Case Summary and Quiz

After reviewing the case summary, consider these questions:

1. What could account for the DAT being negative when Mr. F.S. appears to be experiencing a delayed hemolytic transfusion reaction? [View Answer]
2. Describe the course of alloimmunization to red cell antigens.  [View Answer]
3. a. What percentage of group B Rh positive donors would be expected to be crossmatch-compatible with Mr. FS? [View Answer]
   b. Given the patient's antibodies, what is the minimum number of donors that would need to be antigen typed to obtain two antigen-negative donors to crossmatch? [View Answer]
4. When multiple antibodies are present, which antigen should be typed for first? Besides typing with commercial antisera, are there other ways to screen donors? [View Answer]
5. How common is it for patients with serologic evidence of delayed hemolytic transfusion reactions to experience clinical symptoms? [View Answer]

Further Reading

British Columbia Provincial Blood Coordinating Office. Technical resource manual for hospital transfusion services. Vancouver: Provincial Blood Coordinating Office;2000.

Heddle NM, Soutar RL, O'Hoski PL, Singer J, McBride JA, Ali MA, Kelton JG. A prospective study to determine the frequency and clinical significance of alloimmunization post-transfusion. Br J Haematol 1995 Dec;91(4):1000-5. [ Medline ]