Lesson 4-7 Rh Typing

Rh Blood Group System Discovered in 1940s Second most important group after ABO See Table 4-15 Complex system, over 50 antigens D is most important Ag in group

Rh Blood Group System Rh antigens only on RBCs No naturally occurring Ab ~ 85% of U.S. population is D+ See Table 4-16

Detection of Rh D Slide test Tube test Gel test Agglutination is positive result Only test for D antigen Patient blood + anti-D D positive cells agglutinate with anti-D Tube test Gel test

Detection of Rh Antigens Weak D antigen Reacts weakly in slide test Further testing required Antiglobulin test Blood considered D positive Rh antigens other than D C, c, E, and e most important after D

Rh Antibodies Do not occur naturally Produced after exposure to Rh antigen Transfusion Pregnancy

Rh Antibodies IgG class Importance of Rh typing Must be done before transfusion Identifies risk of HDN

Nomenclature Three nomenclatures See Table 4-17 Fisher-Race Weiner Rosenfield

Inheritance Rh antigens are products of codominant genes RHD gene RHCE gene: 4 alleles See Table 4-18

Hemolytic Disease of Newborn Causes Symptoms and consequences Prevention Identify at-risk mothers by Rh typing Administer Rh immune globulin (RhIG)

Rh Typing Procedures Safety precautions Quality assessment Slide typing Whole blood + anti-D Heated light box Agglutination is positive result

Rh Typing Procedures Tube typing Preferred method Forward typing only Patient cells + anti-D Grade agglutination

Rh Typing Procedures Interpreting results Gel typing Agglutination is positive result Confirm negative result with weak D test Any degree of agglutination is considered D positive See Table 4-19 Gel typing This project was funded at $3,000,000 (100% of its total cost) from a grant awarded under the Trade Adjustment Assistance Community College and Career Training Grants, as implemented by the U.S. Department of Labor’s Employment and Training Administration. Rogue Community College is an equal opportunity employer/program. Auxiliary aids and services, alternate form and language services are available to individuals with disabilities and limited English proficiency free of cost upon request.   This work is licensed under a Creative Commons Attribution 4.0 International License.