CAP Pro Course - Blood Bank - ABO Typing Discrepancies (2025 & 2026)

Author: Rory Huschka, M.Ed., MLS(ASCP)
Reviewer: Laurie Bjerklie, MA, MLS(ASCP)CM

Continuing Education Credits

Objectives

  • Interpret ABO typing results.
  • Identify ABO typing discrepancies.
  • Identify and utilize problem solving strategies.
  • Select ABO compatible blood components for transfusion.

Course Outline

  • Interpret ABO typing results.
      • ABO Typing Results
      • Testing Patient Samples in Pretransfusion Testing
      • ABO Typing of Infants
      • Typing Donor Units
      • A type and screen are ordered on a 52-year-old anemic patient in the emergency department. The medical laboratory scientist searches the patient's his...
      • A cord blood specimen is received in the blood bank on a newborn that appears jaundiced. The following are the results of the blood typing:Forward (Ce...
      • Which of the following represents the appropriate testing and correct results on a cord blood specimen for a newborn determined to have group O blood?...
  • Identify ABO typing discrepancies.
      • Discrepancies
      • Mismatch with Previous Results
      • Serologic Typing Discrepancies
      • Weak or Missing Forward Reactions
      • Unexpected Forward Reactions
      • Weak or Missing Reverse Reactions
      • Unexpected Reverse Reactions
      • A 62-year-old patient with multiple myeloma has begun to experience shortness of breath and bruising on the hands and arms. The physician determines t...
      • A type and screen has been ordered on a 36-year-old patient in preparation for an upcoming surgery. The patient's history states they are group A. The...
  • Identify problem solving strategies.
      • Steps in Solving Typing Discrepancies
      • Are the Antigens or Antibodies Weakly Expressed or Are They Missing?
      • Problem-solving Grid
      • The typing results from a patient are summarized below:Forward (Cell) Typing Reverse (Serum) Typing Reagent Anti-AAnti-B A1 cellsB CellsInterpretation...
      • The following are type and screen test results:Forward (Cell) Typing Reverse (Serum) TypingReagent Anti-AAnti-B A1 cellsB CellsInterpretationResults2+...
      • The following results were obtained from a 60-year-old patient with a history of gastrointestinal bleeding. On multiple occasions, including a recent ...
  • Select ABO compatible blood components for transfusion.
      • Blood Component Compatibility - Whole Blood
      • Blood Component Compatibility - Red Blood Cells
      • Blood Component Compatibility - Plasma
      • Blood Component Compatibility - Platelets
      • The results below were obtained on a specimen collected from a patient. Three units of Red Blood Cells have been ordered for the patient. Based on the...
      • The second trauma pack (five Red Blood Cells, five Plasma) has been requested for a patient in the trauma bay of the ER. A specimen has been collected...
      • After performing an initial ABO type on the patient below, the medical laboratory scientist (MLS) notes that the forward and reverse typing results ar...
      • During surgery, a patient's physician requested one unit of Apheresis Platelets for transfusion. The patient has been typed multiple times as group A....
  • References
      • References

Additional Information

Level of Instruction: Intermediate
Intended Audience: This program is designed as an educational and training tool for MLS, MT, and MLT personnel, medical laboratory science students and interns, pathology residents, and practicing pathologists.
Author Information: Rory Huschka, M. Ed., MLS(ASCP), has over 20 years of combined experience as a medical technologist, technical supervisor, professor, and manager. He is a former Program Director of the Medical Laboratory Science and Medical Laboratory Technician Programs. Rory holds a BS degree in Medical Technology from North Dakota State University and a Master's degree in Educational Leadership. 
Reviewer Information: Laurie Bjerklie, MA, MLS(ASCP)CM, is currently an 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.

This course is part of the CAP Competency Assessment Hub.

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