Rh phenotypes

D antigen frequency is most common in Asians (99%) and is slightly less common in Blacks (92%) and Caucasians (85%). 

Most D positive phenotypes have a conventional D antigen; however variations in antigen structure can result in either a weak D or partial D phenotype (1-2% of Caucasians). Patients with D variant phenotypes may produce anti-D if immunised with D positive red cells and in this situation, it is recommended they be transfused with D negative red cells.

Clinically, weak D individuals of types 1, 2, 3, 4.0, 4.1 and 5 can be treated as D positive and be transfused with D positive red cells, while patients with weak type 4.2-11 and 15 should be treated as D negative and transfused with D negative red cells. 

Partial D individuals can have different epitope expression and induce specific antibody production. As a result, they should be considered D negative and transfused with D negative red cells.

D negative phenotype is most common in Caucasians (15%), less common in Blacks (8%) and rare in Asians (1%).
 

Classification of Rh Phenotype and Genotype

Serology results from testing red cells with the five main Rh anti-sera, the Rh phenotype and probable RH genotype are shown in the following table:

Rh Positive

Serology results and combined data Phenotype Probable genotype Shorthand symbol Approximate % frequency in Australia Other possible genotypes
D+ C+ E- c+ e+ CcDee CDe/cde R1r 35.3 CDe/cDe cDe/Cde
D+ C+ E- c- e+ CCDee CDe/CDe R1R1 17.3 CDe/Cde
D+ C+ E+ c+ e+ CcDEe CDe/cDE R1R2 13.5

CDe/cdE
cDE/Cde
CDE/cde
cDe/CDE
cDe/CdE

D+ C- E+ c+ e+ ccDEe cDE/cde R2r 12.3 cDE/cDe
cDe/cdE
D+ C- E+ c+ e- ccDEE cDE/cDE R2R2 2.3 cDE/cdE
D+ C- E- c+ e+ ccDee cDe/cde R0r 1.7 cDe/cDe

Rh Negative

Serology results and combined data Phenotype Probable genotype Shorthand symbol Approximate % frequency in Australia Other possible genotypes
D- C- E- c+ e+ ccdee cde/cde rr 16.4  
D- C+ E- c+ e+ Ccdee Cde/cde r’r 0.4  
D- C- E+ c+ e+ ccdEe cdE/cde r”r 0.7  

Notes: Frequencies are based on blood group statistics of Australian blood donors; Cells giving a positive reaction with anti-C may be further subdivided by testing with anti-Cw; Other Rh genotypes may be found but all have a frequency of <0.2%.
 

References 
  1. Daniels G, 2013, Variants of RhD – current testing and clinical consequences. British Journal of Haematology, 161: 461-470
  2. Fung MK, Eder AF, Spitalnik SL & Westhoff CM, 2017, AABB Technical Manual 19th Edition
  3. Reid ME, Lomas-Francis C, Olsson ML, 2012, The Blood Group Antigen Facts Book 3rd Edition
  4. Rizzo C et al, 2012, Weak D and partial D: our experience in daily activity. Blood Transfusion, 10(2): 235-236
  5. Sandler SG, Chen LN, Flegel WA, 2017, Serological weak D phenotypes: a review and guidance for interpreting the RhD blood type using the RHD genotype, British Journal of Haematology, 179:10-19