The Disappearing Antibody: A Case Study (by LabCE)

2 P.A.C.E. contact hour(s)

(based on 471 customer ratings)

Author: Pat Letendre, M.Ed., MT(CSMLS)
Reviewer: Suzanne H. Butch, MA, MLS(ASCP)CM, SBB, DLM

Course provided by LabCE.

Mr. R.M., a 55-year old male, was admitted to a hospital emergency department with severe lower gastrointestinal bleeding. His physician orders an emergency transfusion of O Rh-negative Red Blood Cells, but problems arise when the laboratory discovers the presence of an antibody. This interactive case study will allow you to work through Mr. R.M.’s case that becomes even more curious when the antibody apparently disappears.

See more courses in: Blood Banking / Immunohematology

Continuing Education Credits

P.A.C.E.® Contact Hours (acceptable for AMT, ASCP, and state recertification): 2 hour(s)
Course number 578-063-22, approved through 7/31/2024
Florida Board of Clinical Laboratory Personnel Credit Hours - General (Blood Banking / Immunohematology): 2 hour(s)
Course number 20-925669, approved through 7/31/2024


  • Describe possible serological test results in a patient experiencing a hemolytic transfusion reaction.
  • Describe the characteristics of mixed-field agglutination and explain the significance of a positive DAT with mixed-field agglutination in a recently transfused patient.
  • Identify the problems involved in antigen phenotyping patients who have been recently transfused and those who have a positive DAT.
  • List the signs and symptoms of immediate and delayed hemolytic transfusion reactions and differentiate which ones are associated with severe acute hemolytic reactions.
  • Identify antibodies using an antigram and antibody exclusion protocol.
  • Apply standard good laboratory practices to confirm the logical consistency of antibody identification test results and related clinical data.
  • Evaluate serological and clinical inconsistencies when identifying antibodies to determine if further investigative tests are required.
  • Discuss the risks of transfusing un-crossmatched Red Blood Cells and explain when the risks may be acceptable.

Customer Ratings

(based on 471 customer ratings)

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Course Outline

  • Case Scenario
      • Case Presentation
      • Transfusion Service Laboratory
  • Test Results
    • Compatibility Testing
      • Crossmatch Results
      • Pretransfusion Direct Antiglobulin Test (DAT) Result
    • Post-transfusion Tests
      • Post-Transfusion DAT Results
      • Antibody Investigation
      • Other Post-Transfusion Tests
      • Consulting the Patient's Physician
      • Follow-up With Clinical Staff
      • Immediate Hemolytic Transfusion Reaction (HTR): Signs and Symptoms
      • Cause of Delayed HTR
      • Delayed HTR: Signs and Symptoms
      • Signs and Symptoms - Precaution
      • Investigating Weak Antibodies
      • Antibody Identification (2 weeks post-transfusion)
      • Antibody Exclusion Protocol
      • Variations in Antibody Strength
      • DAT Change of Status
      • Antigen Phenotyping
      • Antigen Phenotyping Issues
      • Antigen Phenotyping Results
  • Post-Analytic Check of Data
      • Evaluating Inconsistencies
      • Unexpected Anomaly
      • Reflecting on Probability of the Solution
      • Using Probability (p) Values
      • Antibody Identification Checklist
  • Case Outcome
      • Case Study Summary
      • Risks of Transfusing Unmatched Red Blood Cells
      • Balancing the Risks
  • References
      • References

Additional Information

Level of instruction: Intermediate

Intended Audience: Clinical laboratory technologists, technicians, and pathologists. This course is also appropriate for clinical laboratory science students and pathology residents.
Author information: Pat Letendre, M.Ed., MT(CSMLS), is a laboratory technologist, educator, and consultant. Currently, she consults full-time in the areas of transfusion medicine, education, professional development, and the use of the Internet in education. Ms. Letendre is the Webmaster for the Canadian Society for Transfusion Medicine and the TraQ website coordinator. She holds a Masters of Education degree in adult education from the University of Alberta and a Bachelor of Science degree from the University of Manitoba.  
Reviewer information: Suzanne H. Butch, MA, MLS(ASCP)CM, SBB, DLM is currently working on special projects for the Department of Pathology at Michigan Medicine in Ann Arbor, Michigan. She formerly worked in Quality Assurance in the Department of Pathology and as the Administrative Manager for Healthcare, Blood Bank & Transfusion Service at the University of Michigan Hospitals and Health Centers in Ann Arbor, Michigan. She holds a Bachelors in Medical Technology from the University of Michigan, a Masters Degree in Management and Supervision from Central Michigan University, and Certifications as a Specialist in Blood Bank, as a Quality Audit, and as a Diplomate in Laboratory Medicine. She has edited books and written numerous book chapters and articles and has been invited to present numerous lectures in the field of computerization in the blood bank, automation, and transfusion medicine.
Course description: This course presents a case in which a patient has an unexpected antibody that disappears after he is transfused with unmatched group O Rh negative red blood cells.

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