In the event of a positive antibody screen the laboratory will perform an antibody investigation.  It is essential to identify the antibody specificity to ensure that compatible blood can be provided and to ensure the correct management of pregnancies at risk of haemolytic disease of the newborn.

Patient plasma is tested against red cells which a known antigenic profile to allow investigation. 

In the event of more complex investigations, or where the antibody specificity cannot be determined samples will be referred to an NHS Blood and Transplant Red Cell Immunohaematology Laboratory.  They will complete antigen typing where necessary to confirm presence of an antibody.

Sample type: Blood

Sample requirements: 

7.5ml EDTA sample for adult patients

1.2ml EDTA sample for paediatric patients

- We understand that a full sample cannot always be obtained.  The laboratory will always try to test any sample but in some cases it may be necessary to request a new sample if the volume is insufficient for the test requested.  In such cases the requestor will be informed immediately.

In some cases, it may be necessary to request further samples in order to complete antibody investigations.  The laboratory will contact the requestor immediately if this is the case.

Ensure that sample tube expiry is checked prior to venepuncture.

Sample must be hand labelled and contain the following information:

  • Hospital number
  • Forename
  • Surname
  • Date of Birth
  • Patient location
  • Date and time of collection
  • Signature of collector

The request card must contain the following:

  • Hospital number
  • Forename
  • Surname
  • Date of birth
  • Sex
  • Patient location
  • Date and time of collection
  • Requesting Practitioner Signature (including medical officer/Midwives)
  • Name and signature of person taking sample (The name and signature should be completed in the box stating Patient ID checked and confirmed)

To minimise the risk of transcription error addressograph labels are encouraged to be used on the request card.

The request card should also be used to detail if the patient has any special requirements for transfusion, for example: Irradiated products.

In addition for Antenatal requests (Green Antenatal blood form) please include:

  • Gravida
  • EDD
  • Date and dose or any recent anti-D prophylaxis

IMPORTANT: The Trust operates a zero tolerance policy.  Failure to observe the requirements for sample and request card labelling will result in sample rejection and a repeat requested.

Sample validity: 72 hours at 2-8oC Samples should be sent to the laboratory immediately.  Improper storage of samples can lead to potential sample deterioration. Any samples which arrive in the laboratory 12 hours or more after venepuncture will not be tested.

Turnaround time: Varies with the complexity of case