Crossmatch

Description: 
ABO compatible packed red cell units may be issued to a patient when there have been 2 Blood Group and Antibody Screens completed. A sample may be used for crossmatch up to a maximum of 8 weeks from collection date where the patient is not pregnant, has not been transfused and does not have a positive antibody screen. In other cases please contact the laboratory to check sample validity. Most red cells are electronically issued to patients. When a patient is not eligible for electronic issue a full crossmatch must be performed. This will typically be where the patient has a current or historical positive antibody screen recorded or where the pre transfusion group and screen result has been manually edited on that sample.
Clinical details: 
For further information please refer to the GSTT Clinical Guidance Policy.
http://tww-wafr/WAFR-FAD/Applications/ClinicalGuidance/User/Details.aspx?id=4971
Reference range: 

N/A

Units: 
N/A
Department: 
Blood Sciences Department
Location: 
St Thomas' Hospital
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) with high plasma to cells ratio.
Call in advance: 
Yes
Patient instructions: 

 

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

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.

Criteria for acceptance / rejections of sample
Storage and transport: 
Sample Retention: Samples are stored for 7 days.
Contacts:
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.
Laboratory: 
Blood Transfusion Laboratory at Guy's and St Thomas' Hospital

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Last updated: 08/08/2022