The Disappearing Antibody: A Case Study (Online Course)

(based on 477 customer ratings)

Author: Pat Letendre, MEd
Reviewer: Cindy Lee Jones, MS, MT(ASCP)

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 all available courses »

Continuing Education Credits

  • P.A.C.E.® Contact Hours: 2 hour(s)
  • Florida Board of Clinical Laboratory Science CE - General (Blood Banking / Immunohematology): 2 hour(s)
  • Florida Board of Clinical Laboratory Science CE - General (Immunohematology): 2 hour(s)

Objectives

  • 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 477 customer ratings)

Course Outline

  • Case Scenario
      • Case Presentation
      • Transfusion Service Laboratory
  • Test Results
    • Compatibility Testing
      • These ABO, Rh, and antibody screen results were obtained by the transfusion services laboratory using the blood specimen that was collected prior to s...
      • The antibody screen is positive but the transfusion of the O Rh-negative RBCs is already in progress. What are the transfusion service (TS) laboratory...
      • Crossmatch Results
      • Pretransfusion Direct Antiglobulin Test (DAT) Result
    • Post-transfusion Tests
      • Post-Transfusion DAT Results
      • Which of the following statements about mixed-field agglutination (MFA) are true? Select all that are correct.
      • In this case, which red blood cells (RBCs) are agglutinating in the DAT and why?Antibody screen Cells Gel IAT*Screen Cell I 3+Screen Cell II 2+Screen ...
      • Antibody Investigation
      • Which of the following most likely accounts for the patient's post-transfusion plasma giving negative panel results?
      • 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
      • Which of the following signs and symptoms is most likely to indicate a severe immediate hemolytic transfusion reaction?
      • Investigating Weak Antibodies
      • Antibody Identification (2 weeks post-transfusion)
      • Antibody Exclusion Protocol
      • Using the guidelines in the Antibody Exclusion Protocol, which antibodies are possible (have not been excluded) using this panel? Select all that appl...
      • Which of the following antibodies in this scenario could explain all reactions by itself? Antibody identification results Cell ...
      • Which of the following cells would be the one most useful cell to exclude both anti-E and anti-K in this patient?
      • Variations in Antibody Strength
      • When the patient's plasma was non-reactive with panel cells, and very weak and unidentifiable in the post-transfusion RBC eluate, no attempt was made ...
      • DAT Change of Status
      • Antigen Phenotyping
      • Antigen Phenotyping Issues
      • Antigen Phenotyping Results
      • Which of the following statements about antigen phenotyping are TRUE? (Select all that apply)
  • Post-Analytic Check of Data
      • Evaluating Inconsistencies
      • Unexpected Anomaly
      • Reflecting on Probability of the Solution
      • When performing an antibody investigation, which of the following would indicate an inconsistency that needs to be further investigated? (Select all t...
      • The patient's red cell eluate initially was unidentifiable, reacting weakly with only two panel cells that did not fit a pattern. Once anti-Jka was id...
      • Using Probability (p) Values
      • Antibody Identification Checklist
      • As discussed earlier, one of the post-analytic tools for confirming that the serologic data fit the solution is to consider the big picture, as presen...
  • Case Outcome
      • Case Study Summary
      • Risks of Transfusing Unmatched Red Blood Cells
      • Balancing the Risks
      • Think about your responses to each of the following questions, then click on the questions.
  • 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,  is a laboratory technologist, educator, and consultant. Currently, she consults full-time in the areas of transfusion medicine, education, professional development, and 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: Cindy Lee Jones, MS, MT(ASCP) is the senior blood bank technologist at University Hospital, Albuquerque, New Mexico. She holds a BS in Medical Technology and an MS in Horticulture from New Mexico State University.  In her present position, she is responsible for the coordination of student rotation and the instruction of technologist/technician students and pathology residents in immunohematology.
 
Course description: This course presents a case in which a patient has an unexpected antibody that disappears after he is transfused with 2 units of uncrossmatched group O Rh-negative RBCs. Several blood banking procedures and issues are covered including antibody identification, direct antiglobulin testing, recognition and response to hemolytic transfusion reaction, and antigen phenotyping.
 




Antibody screen cells


Post-transfusion microscopic DAT


DAT micro4