CAP Pro Course - Blood Bank - Direct Antiglobulin Test (2026 & 2027)

Author: Suzanne Butch, MA, MLS(ASCP)CMSBB, DLM
Reviewers: Patrick Tracy, MA, MLS(ASCP) and Laurie Bjerklie, MA, MLS(ASCP)CM

Continuing Education Credits

Objectives

  • Discuss the basic principles of antiglobulin testing and clinical indications for direct antiglobulin testing (DAT).
  • Describe serological procedures used in DAT testing and the preanalytical and analytical variables that may influence results.
  • Identify clinical conditions that may cause positive DAT results.
  • Describe common methods used in the investigation of a positive DAT.

Course Outline

  • Discuss the basic principles of antiglobulin testing and clinical indications for direct antiglobulin testing (DAT).
      • Antiglobulin Testing Principles
      • Antibody-Coated Control Cells
      • Clinical Indications for Direct Antiglobulin Testing
      • Anti-human Globulin Reagents
      • Which antihuman globulin (AHG) reagents would be best at detecting only a cold-reacting IgM antibody bound to red cells?
      • If an AHG reagent is labeled "heavy gamma chain specific," which immunoglobulin class will it detect?
      • A patient who was last transfused six months ago is being treated with antibiotics for an infection and has low hemoglobin but no signs of bleeding. T...
      • Which one of the following statements is true regarding the direct antiglobulin test (DAT)?
  • Describe serological procedures used in DAT testing and the preanalytical and analytical variables that may influence results.
      • DAT Specimen Requirements
      • DAT Serological Procedures
      • Prior to surgery, a pre-transfusion workup on patient F resulted in an ABO discrepancy. Records show that patient F has a history of cold agglutinin s...
      • An EDTA specimen from patient G is received with an order for a DAT. The blood bank personnel centrifuges the tube, separates the plasma from the cell...
      • Which one of the following causes of potential false-negatives in monospecific IgG DAT reactions cannot be controlled for by using IgG-coated check ce...
  • Identify clinical conditions that may cause positive DAT results and variables that may cause false-positive and false-negative results.
      • Interpretation of Positive DAT Results
      • Autoimmune Hemolytic Anemia (AIHA)
      • Hemolytic Transfusion Reactions (HTRs)
      • Drug-Induced Hemolysis
      • Hemolytic Disease of the Fetus and Newborn (HDFN)
      • Preanalytical and Analytical Variables That May Produce False-Positive DAT Results
      • Preanalytical and Analytical Variables That May Produce False-Negative DAT Results
      • A group-B infant with a group-O mother has jaundice and is suspected of having ABO hemolytic disease of the fetus and newborn. Which one of the follow...
      • A patient was seen by their physician two weeks after surgery because of tiredness, lethargy, and yellowing of the eyes. The patient received three un...
      • Which of the following statements is correct about interpreting the results of a DAT in a transfusion reaction investigation?
      • Which of the following cases is most likely to result in a case of hemolytic disease of the fetus and newborn (HDFN)?
  • Describe common methods used in the investigation of a positive DAT.
      • Evaluation of Positive DAT Results
      • Elution Techniques
      • Adsorption Techniques
      • Evaluation of Positive DATs in Newborns
      • Which one of the following elution methods would be best for investigating a positive DAT in a suspected case of passive infusion of incompatible ABO ...
      • In which one of the following situations is the patient likely to have a positive DAT and a negative antibody screen?
      • A group-A newborn with a group-O mother has a positive DAT. Which eluate technique is best to confirm the cause of the positive DAT?
  • References
      • References

Additional Information

Level of Instruction: Intermediate
Intended Audience:  This program is designed as an educational and training tool for MLS and MLT personnel, medical laboratory science students and interns, pathology residents, and practicing pathologists.
Author Information:  Suzanne H. Butch, MA, MLS(ASCP)CMSBB, DLM, is 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 bachelor's degree in Medical Technology from the University of Michigan, a master's 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. 
The author has no conflict of interest to disclose. 
Reviewer Information:
Patrick Tracy, MA, MLS(ASCP), has been an MLT program director since 2012. His teaching experience has been in student labs, both face-to-face and online. His contribution to medical laboratory education is most pronounced by his microbiology, blood bank, and chemistry YouTube channel.
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.

This course is part of the CAP Competency Assessment Hub.

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