ABO Typing Discrepancies
Continuing Education Credits
Discrepancies in ABO typing lead to delays in determination of products that are safe to transfuse to the patient. When the ABO type has not clearly been determined, transfusion of universal donor red cells and plasma are necessary, thus depleting the supply of these products. It is important to know the possible causes of ABO discrepancies in order to develop algorithms and standard procedures to resolve them quickly. This course will provide a general scheme for resolving ABO discrepancies and work through examples cases.
Objectives
- Discuss ABO testing and result interpretation.
- Identify the types of ABO discrepancies and explain the impact that discrepancies can have upon patient care and patient safety.
- Detect an ABO discrepancy and apply serological techniques to resolve the error to ensure the correct ABO type is reported.
- Discuss how different test methodologies, including tube, column agglutination, and solid phase, produce varying results with regard to discrepant ABO types.
- Analyze pre-examination, examination, and post-examination steps to uncover a potential ABO discrepancy.
Course Outline
- Introduction
- Overview
- Basics of Immunology and ABO Testing
- Immunology Principles
- Antigen/Antibody Interaction
- Antigens and Antibodies
- Affinity and Avidity
- Zeta Potential and van der Waals Forces
- Agglutination
- Agglutination Chart
- Antigens and antibodies specifically combine to form immune complexes. What term refers to the antibody's attraction to a particular antigenic determinant (epitope)?
- Match the explanation, description, or definition to its correct immunology term.
- ABO Testing
- ABO Groups and Frequencies
- ABO Testing and Interpretation
- Review the following test results and match the expected reaction pattern to the reported ABO type.
- ABO Typing Discrepancies
- ABO Typing Discrepancies
- Classifying ABO Discrepancies
- ABO Discrepancies Related to Subgroups of A or B
- Weakened or Missing Reactions in the Reverse Typing
- Acquired B Phenomenon
- Plasma Protein-Related Discrepancies
- Miscellaneous Causes of ABO Discrepancies
- A patient's pretransfusion ABO grouping results are displayed in Table 12.Table 12. Pre-Transfusion Patient Results.Anti-AAnti-BA1 cellsB cells Patient Results4+000What is the likely ABO group for this patient and what ABO typing discrepancy is most descriptive of these findings?
- Resolution Strategies
- Pre-examination Considerations
- ABO Discrepancy Resolution: General Guidelines
- Reagents and Techniques/Testing Methods Used in ABO Discrepancy Resolution
- Example: Weak/Missing Reaction in the Forward Typing
- Example: Weak/Missing Reaction in the Reverse Typing
- Incubate at Room Temperature or Refrigerator
- Example: Unexpected Reaction in Forward Typing
- Example: Unexpected Reaction in Reverse Typing
- Reverse Typing Discrepancies: Identify the Unexpected Antibody
- Auto Control and O Cell Control
- Testing with Lectins
- In Addition To... Not a Replacement Of...
- Concurrent Result Documentation to Prevent Errors
- Comparison of Testing Methodologies
- ABO Testing Methodologies
- Stepping Back to Resolve an ABO Discrepancy
- Case Studies: Resolving Discrepancies on the Bench
- Case Study 1An 83-year-old patient is undergoing pre-op testing, which includes a type and screen with a 2-unit red cell crossmatch. One 7 mL EDTA tube was collected and labeled with the full name, date of birth, medical record number, collection date and time, and the collector's initials. The sample was acceptable per the blood bank's specimen acceptability procedure. The sample was processed an
- Case Study 2A 38-year-old patient has a history of chronic anemia, which has resulted in 4 previous allogeneic packed red blood cell transfusions. At present, she is experiencing lethargy, pallor, shortness of breath, and extreme malaise. Her physician orders hemoglobin testing, which results in a value of 7.0 g/dL. Upon review of the testing, her physician orders pretransfusion testing and 2 unit
- Case Study 3 A 36-year-old patient has a history of gastrointestinal conditions, including Crohn's Disease. He has been admitted to the hospital for a general surgical procedure related to his condition. Preoperative lab work has been ordered and includes a type and screen. Results are displayed in Table 22. Review the results and determine if there are any potential issues with the reported reac
- Case Study 4 A 44-year-old patient has a history of rheumatoid arthritis and chronic anemia, historically treated with diet and iron supplements. She has recently experienced extreme lethargy and malaise that have forced her to seek medical intervention. Upon a doctor's visit, labwork demonstrated a hemoglobin level of 7.3 g/dL. Her physician decides to order a one-unit red blood cell transfusion
- Case Study 5 A 48-year-old patient has been hospitalized with an infection of Mycoplasma pneumoniae. At the patient's request, her physician has ordered a blood type, although there is no medical necessity for this order as the patient is not anemic nor preparing for surgery. The patient vaguely recalls that her type is AB but desires confirmation. Typing results were collected and displayed in T
- 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: Candice Freeman, Ph.D., MLS(ASCP)BB is the Administrative Lab Director at Scotland Health in Laurinburg, North Carolina. She also holds adjunct faculty positions at Winston-Salem State University and Appalachian State University, where she teaches online courses in clinical laboratory science and teacher education. With over 30 years of experience in clinical laboratories and higher education, Dr. Freeman brings a varied and diverse background of laboratory and quality improvement performance experience to healthcare workforce development. Dr. Freeman is a certified Medical Laboratory Scientist through ASCP and also has certifications in Google, NAHQ, ASQ, and CoSN. Dr. Freeman holds an MA.Ed. in Social Media and Global Education and a Ph.D. in Instructional Design and Education Technology.
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 15 years of experience in higher
education and has held program director and faculty positions in both MLT and
MLS programs.