Red Cell Phenotype

Phenotype testing is commonly performed as further confirmation of a newly detected antibody. The RH (C, c, E, e) and Kell phenotypes will also be done locally so that units selected for further crossmatches will expose the patient to less foreign antigens. Extended Phenotyping may be performed on Sickle Cell patients who are to begin an exchange transfusion regime; this is referred to the National Blood Service.
Clinical details: 
For further information please refer to the GSTT Clinical Guidance Policy.
Sample type and Volume required: 
Griener Vacutte K3EDTA 6 mls whole blood for adult tube (Pink top)
Griener Vacutte K2EDTA 4 mls whole blood for adult tube (Purple top)
K3EDTA paediatric 1 ml whole blood tube (pink top)
Call in advance: 
Special sample instructions: 

Samples for Transfusion testing must include the following minimum details:

All details must be legibly handwritten on the blood tube.

Surname (in full)

Forename (in full)

GSTT Hospital Number*

Date of Birth

Date and time of sample


Signature of the person taking the sample

*Most samples from GP surgeries may be accepted without a hospital number. However samples for transfusion testing on antenatal patients must always have a GSTT hospital number.

Factors affecting the results: The interpretation of red cell phenotype results can be complicated if the patient has received a Blood Transfusion within the last three months, post bone-marrow transplant, or post massive foetal-maternal haemorrhage. Unexpected results may occur due to to the patient’s underlying condition e.g. autoimmunity causing a positive auto control that will invalidate the test.

Storage and transport: 
Sample Retention: Samples are stored for 7 days.
Blood Transfusion Laboratory at Guy's and St Thomas' Hospital
020 7188 4774
Blood Transfusion Laboratory
St Thomas' Hospital
North Wing, 5th Floor
St Thomas' Hospital
Westminster Bridge Road
London SE1 7EH

Blood Transfusion Laboratory
Guy's Hospital
Southwark Wing, 4th Floor
Great Maze Pond
London SE1 9RT
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 24/05/2022