Overview Of Major Antigens of the Rh Blood Group System

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Author: Pamela Inglish, MT (ASCP)SBB
Reviewers: Jessica M. Mantini, MS, MLS(ASCP)CM; Suzanne H. Butch, MA, MLS(ASCP)CM

This course aims to provide the learner with an overview of the Rh blood group system, to review the unique characteristics of the antigens and antibodies of the system, to describe the naming conventions associated with the system, and to stimulate an appreciation for the complexities of the Rh system. The content provided is written with the assumption that the learner has a basic understanding of immunohematology and the ABO blood group system prior to taking this course.

Continuing Education Credits


  • Recall the five major antigens of the Rh blood group system.
  • Describe and compare several terminologies/nomenclature conventions commonly used when discussing the Rh blood group system.
  • List the characteristics of the Rh blood group system, including basic biochemical and molecular composition as well as chromosome location and inheritance.
  • Describe four mechanisms that may result in weakened expression of the D antigen.
  • List characteristics of antibodies commonly encountered in the Rh blood group system, phase of reactivity, ability to cross the placenta, and effect of enzyme treatment during testing.

Course Outline

  • Overview of Rh
      • Introduction to the Rh System
      • History of Rh and association with LW
    • Practice questions
      • Rh typing is considered extremely important in pre-transfusion testing because:
      • The antibody that reacts with most D-positive red blood cells (RBCs), weakly with D-negative RBCs and NEVER with Rhnull RBCs is:
  • Genetics/biochemistry
      • Genes of the Rh System
      • Biochemical and Functional Characteristics of Rh
  • Nomenclature or terminology and inheritance in the Rh system
      • Terminology
      • Fisher-Race DCE Terminology
      • Haplotype prevalence (%) in Fisher-Race terminology
      • Wiener Rh-Hr Terminology
      • Fisher-Race and Wiener Terminology Road-map
      • Rosenfield Alphanumeric Terminology
      • ISBT Numeric Terminology
    • Practice questions
      • Which of the following are terminologies used for the Rh blood group system?
      • Using Rosenfield terminology and the possible answers below, select the correct way to write the phenotype for a red cell sample that reacts as follow...
      • Match the correct Wiener shorthand with the Fisher-Race designation provided.
      • From the choices given below, select the most likely Fisher-Race designation for the individual whose red cells test as follows:D +C+E negc +e+
  • Rh system antigens and several important genetic alterations
      • Rh Antigens of Clinical Importance
      • Alterations in D Antigen Expression
      • Four Mechanisms of Weakened Expression of the D Antigen
      • Mechanism 1: C in trans to RHD
      • Mechanism 2: Weak D
      • Mechanism 3: Partial D
      • Mechanism 4: Del
      • Deletion, null and mod Phenotypes in the Rh System
      • Inheritance of the Rhnull and Rhmod Phenotypes
      • Other Unusual Phenotypes and Rare Alleles in the Rh System
    • Practice questions
      • Select all items from the list below representing mechanisms that will result in weakened expression of the D antigen.
      • From the list below, select all of the items that represent null or deletion phenotypes.
  • Characteristics of Rh system antibodies
      • Characteristics of Rh Antibodies
      • Screening the Intended Recipient for Alloantibodies, Including Those in the Rh System
  • Laboratory testing for Rh system antigens and antibodies
      • Reagents For Use In Rh Typing
      • False-Positive Reactions With Rh Typing Reagents
      • False-Negative Reactions With Rh Typing Reagents
      • Rh Testing For Blood Donors and Labeling Blood Products
    • Practice questions
      • Reagents manufactured from a single clone of antibody-producing cells are called:
      • Which of the following situations can result in a false-negative reaction with Rh typing reagents?
  • Clinical considerations related to the Rh system
      • Hemolytic Disease of the Fetus and Newborn (HDFN)
      • Hemolytic Transfusion Reaction (HTR)
      • Special Considerations for Chronically or Multiply Transfused Patients
      • Clinical Significance of Rhnull and Rhmod
    • Practice questions
      • From the choices below, select all the reasons Rh antibodies are clinically significant.
      • A common practice for preparing red blood cell products for chronically transfused patients is to match Rh phenotype of recipient and donor by testing...
  • Case study
      • Rh Case Study
      • Discussion of Rh Case Study
      • Rh Case Study, Further Testing
      • Rh Case Study, ID Panel crossout
      • Further Discussion of Rh Case Study
  • References
      • References

Additional Information

Level of Instruction: Intermediate 

Intended audience: Medical laboratory scientists, medical technologists, and technicians. This course is also appropriate for medical laboratory science students and pathology residents.

Author information:  Pamela Inglish, MT (ASCP)SBB has 30+ years of experience in medical laboratory sciences having completed training at the Medical College of Virginia/Virginia Commonwealth University. Subsequently, she obtained certification as a Specialist in Blood Banking through AABB/ASCP. For the majority of her career, Ms. Inglish held positions of responsibility in hospital transfusion services, blood centers, and clinical stem cell transplant processing laboratories and has also sold clinical lab diagnostic equipment and reagents. In her most recent position at the University of Cincinnati/Hoxworth Blood Center, she was director of quality assurance and education and served as an adjunct instructor.

Reviewer information: Jessica M. Mantini, MS, MLS(ASCP)CM, is a clinical instructor of Immunohematology at the Ohio State University School of Allied Medical Professions and the Program Director for the Medical Laboratory Science Division. She holds an MS in Allied Health Management from Ohio State University.

Reviewer information: Suzanne H. Butch, MA, MLS(ASCP)CM, SBB, DLM is currently working on special projects for the Department of Pathology at Michigan Medicine in Ann Arbor, Michigan. She formerly worked in Quality Assurance in the Department of Pathology and as 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 Bachelors in Medical Technology from the University of Michigan, a Masters 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. 

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