The Disappearing Antibody: A Case Study
Continuing Education Credits
This course presents a case study involving a patient with an unexpected antibody that becomes undetectable after transfusion with uncrossmatched group O Rh-negative red blood cells.
Objectives
- Describe possible serological test results in a patient experiencing a hemolytic transfusion reaction.
- Explain the characteristics of mixed-field agglutination and 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.
- Evaluate serological and clinical inconsistencies when identifying antibodies to determine if further investigative tests are required.
- Explain the risks of transfusing uncrossmatched red blood cells and when the risks may be acceptable.
Course Outline
- Case Scenario
- Case Presentation
- Initiating Emergency Transfusion
- Test Results
- Compatibility Testing
- The ABO, Rh, and antibody screen results were obtained by the transfusion services laboratory using the blood specimen that was collected prior to starting the emergency transfusion with O Rh-negative red blood cells.ABO and Rh TypingABO Forward GroupABO Reverse GroupRh Anti-AAnti-BA1 cellsB cellsAnti-D004+4+3+Antibody Screen CellsGel IAT*Screen Cell I 3+Screen Cell II 2+Screen Cell III 2+ *IAT
- 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's priorities in this case?Place the following procedures that the TS will follow in the appropriate order of priority.
- Crossmatch Results
- Post-Transfusion Tests
- Pre-Transfusion Direct Antiglobulin Test Result
- Post-Transfusion DAT Results
- Which of the following statements about mixed-field agglutination (MFA) is inaccurate?
- In this case, which red blood cells (RBCs) are agglutinating in the DAT and why?Antibody Screen CellsGel IAT*Screen Cell I 3+Screen Cell II 2+Screen Cell III 2+ *IAT = indirect antiglobulin testPatient CellsDATCCPost-transfusion2+ mixed field agglutination (MFA)N/A CC = check cells
- 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 Signs and Symptoms
- Cause of Delayed Hemolytic Transfusion Reaction
- Delayed Hemolytic Transfusion Reaction Signs and Symptoms
- Signs and Symptoms Precaution
- Which of the following signs and symptoms most likely indicate a severe immediate hemolytic transfusion reaction?
- Investigating Weak Antibodies
- Two Weeks Post-Transfusion Antibody Identification
- 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 apply.CellRh-HrKellDuffyKiddLewisLutheranPMNSsXgResultsRh DCcEeCwKkKpaJsaFyaFybJkaJkbLeaLebLuaLubPMNSsXgaGel IAT1rr00+0+00+00+0+0+00++0+++01+2rr00+0+00+00+0+++00++0++++w+3rr00+0+00+00++0+0+0++0++0004r''r0 0 +++00+00++0++00++0+0+005R2R2+0++00+000++++0+0++
- Which of the following antibodies in this scenario could explain all reactions by itself?CellRh-HrKellDuffyKiddLewisLutheranPMNSsXgResultsRh DCcEeCwKkKpaJsaFyaFybJkaJkbLeaLebLuaLubPMNSsXgaGel IAT1rr00+0+00+00+0+0+00++0+++01+2rr00+0+00+00+0+++00++0++++w+3rr00+0+00+00++0+0+0++0++0004r''r0 0 +++00+00++0++00++0+0+005R2R2+0++00+000++++0+0+++0+00w+6R2R2+0++00++00++++0+0+++0+0+w+7R1R1++00+00+000+0+0+++++
- Which of the following cells would be the most useful in excluding 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 to enhance the weak antibodies.We now know that the patient has anti-Jka, which rapidly disappeared from the patient's plasma after transfusion with group O Rh-negative red blood cells. Consider the question below, then click on the question to receiv
- DAT Change of Status
- Antigen Phenotyping
- Antigen Phenotyping Issues
- Antigen Phenotyping Results
- Which of the following statements about antigen phenotyping is inaccurate?
- Post-Examination 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?
- 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 identified, a check of the eluate panel results showed that both reactive cells were Jk(a+b-), circled in red in the image on the right, but two other Jk(a+b-) panel cells did not react, circled in blue in the image.Consider the question below, then cl
- Using Probability Values
- Antibody Identification Checklist
- As discussed earlier, one of the post-examination tools for confirming that the serologic data fit the solution is to consider the big picture, as presented below. Consider how you would reply to each question in this case, and then click each question to see sample responses.
- Case Outcome
- Case Study Summary
- Risks of Transfusing Unmatched Red Blood Cells
- Balancing the Risks
- Consider your responses to each of the following questions, then click on the questions.
- References
- References
Additional Information
Level of Instruction: Intermediate
Intended Audience: Medical laboratory scientists, medical
laboratory technicians, laboratory supervisors, and laboratory managers. This
course is also appropriate for MLS and MLT students and pathology residents.
Author Information: Pat Letendre, M.Ed., MT(CSMLS), is a medical laboratory scientist, educator, and consultant. She consults full-time in 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 Master of Education degree in adult education from the University of Alberta and a Bachelor of Science degree from the University of Manitoba.
The author has no
conflict of interest to disclose.
Reviewer Information: Laurie Bjerklie, MA, MLS(ASCP)CM, is
a Lead Education Developer. She earned a B.S. in Medical Laboratory Science
from the University of North Dakota and an M.A. in Curriculum and Instruction
from Saint Xavier University. She has over 20 years of experience in higher
education and has held program director and faculty positions in both MLT and
MLS programs.
Course Description: This course presents a case involving a patient with an unexpected antibody that becomes undetectable after transfusion with uncrossmatched group O Rh-negative red blood cells.