Phenotyped components

Phenotyping can be performed for red cell and platelet components.

Phenotyped components are used for these clinical indications:

  • Prevention of alloimmunisation in frequently transfused patients
  • Provision of compatible red cells in patients with clinically significant antibodies

Patients who have a clinically significant antibody, or have a history of a clinically significant antibody should be provided with red cells negative for the relevant antigen. The table provides the frequency of negative phenotypes for antibodies generally considered clinically significant.

Clinically significant antigen frequency

Antigen Frequency of negative phenotype
D 17.9%
C 47.3%
c 17.5%
E 71.6%
e 2.4%
K 90.9%
k 0.4% (rare)
Jka 23.6%
Jkb 26.3%
S 48.0%
S 9.4%
U 0.01% (rare)
Fya 32.7%
Fyb 19.7%

A full list of major blood group phenotypes is available

For patients who have non-clinically significant antibodies, the red cells do not need to be antigen negative for the corresponding antibody.

The following table provides the frequency of negative phenotypes for those antibodies generally considered non-clinically significant.

 

Clinically non-significant antigen frequency

Antigen Frequency of negative phenotype
A1 20% (of group A)
HI (in A1 and A1B) N/A
CW 98%
Kpa 97.8%
M 21.5%
N 29.5%
P1 25.2%
Lea 77.6%
Leb 27.7%
Lea+b 5.3%
Lua 92.3%
Wra 99.9%

For patients with rare red cell phenotypes or phenotypic combination requirements, the Blood Service will need to locate suitable red cell units. If no compatible unit is readily available, the Blood Service may need to:

  • contact particular phenotyped donors to arrange donation,
  • access phenotyped red cells from frozen inventory or
  • request assistance from international Blood Services.
References
  1. Australian & New Zealand Society for Blood Transfusion. Guidelines for Pre-transfusion Laboratory Practice, 5th edition. Sydney: ANZSBT Ltd, March 2007.
  2. National Pathology Accreditation Advisory Council. Requirements for Transfusion Laboratory Practice, 1st edition. Canberra: NPAAC, October 2008.