Case A2: Falling Hemoglobin in a Recently Transfused Patient

We Welcome Feedback: Contact This email address is being protected from spambots. You need JavaScript enabled to view it.

Last Updated: Oct. 10, 2016 [All links fixed]

If you find errors or have suggestions, fire away!

Contributed by Daryl Gouthro, RT St Paul's Hospital Transfusion Service, and Sylvia Luther, RT Matsqui - Abbotsford - Sumas (MSA) General Hospital Transfusion Service




Medications (pre-op)


Mr. F.S. is a 51 year old male diagnosed with recurrent carcinoma of the rectum that is invading the bladder. He was previously diagnosed in 1997 when he underwent a colostomy and post-op radiation.

  • Transfusion history: No recent history of transfusion at St. Paul’s Hospital.

  • Other: Allergy to penicillin

  • Tylenol with codeine
  • Oxybutynin
  • Pyridium
  • Vitamin A +
  • Zinc
  • Vitamin C
  • Vitamin E

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 7th 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.


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:


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?


  2. Describe the course of alloimmunization to red cell antigens.


    1. What percentage of group B Rh positive donors would be expected to be crossmatch-compatible with Mr. FS?


    2. 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?


  3. When multiple antibodies are present, which antigen should be typed for first? Besides typing with commercial antisera, are there other ways to screen donors?


  4. How common is it for patients with serologic evidence of delayed hemolytic transfusion reactions to experience clinical symptoms?



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 ]