Group & Antibody Screen
This test gives results for ABO & Rh(D) group and an Antibody screen which will detect the presence of clinically significant antibodies. A positive antibody screen will automatically initiate further testing to identify the detected antibody. Uncommon ABO & Rh(D) subtypes may be referred to the National Blood Service for further testing and confirmation.
Viapath at St Thomas Hospital uses Bio-Rad ID-System products and reagents which use column agglutination technology to determine antigen-antibody reactions.
Please note: All samples for testing in Blood Transfusion must be hand written and be complete with First Name, Surname, Date of Birth and Hospital number. Viapath adopts a zero tolerance policy on incorrectly or incompletely labelled samples and non compliant labelling will result in sample rejection.
GP samples may be processed without a hospital number, however the reason for Blood group and Antibody screen must be indicated. Requests for antenatal screening must be performed through the appropriate St Thomas clinic and include a hospital number.
Antibody identification is automatically performed on the basis of a positive result in the Blood Group and Antibody screen and is not requested as a lone test. Antibodies are identified through the use of a panel of cells with known phenotypes.
All antibodies are referred to the National Blood Service (NBS) reference laboratory in the first instance for Antibody confirmation and to record the results on a national database. This also results in the patient receiving an Antibody card from the NBS to aid in future testing.
Antibodies detected that cannot be identified locally due to being a low incidence antibody or the presence of multiple antibodies is referred to the NBS reference laboratory.
If indicated an Elution may be performed to identify specificity of antibodies bound to a patients red cells. This is referred to the NBS.
http://tww-wafr/WAFR-FAD/Applications/ClinicalGuidance/User/Details.aspx?id=4971
N/A
Griener Vacutte K2EDTA 4 mls whole blood for adult tube (Purple top)
K3EDTA paediatric 1 ml whole blood tube (pink top) with high plasma to cells ratio.
Routinely a 2-6mls whole blood venous sample is required for adult samples. Paediatric samples require at least 75µl of plasma for the three cell antibody screen, 50 µl of plasma for the reverse group if necessary and 10 µl of the patient’s red cells for the ABO and RhD group.
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
Sex
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 laboratory analysis of ABO/D types may be complicated by anomalous reactions due to unexpected weak reactions, patients with rare variant blood types, presence of additional reactions due to cold alloantibodies or autoantibodies, transfusion of red blood cells, and the occurrence of chimeric bone marrow transplant phenotypes. Haemolysed samples are not suitable for analysis as they may cause false reactions in antibody screens. They will only be accepted for analysis if the patient is undergoing an intravascular haemolytic episode and a non-haemolysed sample cannot be obtained.
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
Last updated: 31/01/2022
