London Regional Transfusion Committee
Blood Grouping and Antibody
Testing in Pregnancy
Training Presentation by iTransfuse
with the London RTC
Based on the BCSH Guideline for Blood Grouping
and Antibody Testing in Pregnancy 2006
London Regional Transfusion Committee
Aim
• By the end of this you should have an
understanding of:
– The tests required during pregnancy
– Why we do the tests
– What antibodies are significant
– What tests are required post delivery
London Regional Transfusion Committee
Purpose of Lab Testing
• ABO and D typing to identify D negative
women who need anti-D
• Antibody screening and ID of red cell
alloantibodies
• Monitor circulating levels of clinically
significant antibodies
London Regional Transfusion Committee
Haemolytic disease of the Newborn
London Regional Transfusion Committee
Antenatal Testing Protocols
• Booking sample testing (ABO and antibody
screen)
– ideally at 10-16 weeks gestation
• Repeat test at 28 weeks gestation (ABO and
antibody screen)
• If antibody screen is positive a full antibody
investigation must be performed
London Regional Transfusion Committee
Clinically Significant Antibodies
• What antibodies are implicated in severe
HDN?
– Anti-D
– Anti-c
– Anti-K
• In addition to these anti-C, -E, -Fya and Jka
• Only IgG antibodies are capable of entering
the foetal circulation
London Regional Transfusion Committee
Women with anti-D
• How can you distinguish between prophylactic
and immune?
– Check transfusion records
• Previous prophylactic anti-D given (within 8 weeks)
• Antibody history?
• Phone ward/GP to check if patient transferred
– Send for D Quantitation
• Anti-D level rarely exceeds 1 iu/ml post prophylaxis
unless a dose of more than 1250 iu has been
administered
London Regional Transfusion Committee
Immune Anti-D
• How often should you test during pregnancy?
– Every 4 weeks until 28 weeks gestation then every
2 weeks until delivery
• What testing should be done?
– Maternal Rh phenotyping
– Anti-D quantitation (every maternal sample)
– Partner sample phenotyping
• Refer patient to Obstetric team
London Regional Transfusion Committee
Concentration of Anti-D
• What levels of anti-D are significant?
Anti-D Level
HDN?
<4 iu/mL
Unlikely
4-15 iu/mL
Moderate risk
>15 iu/mL
High risk of Hydrops fetalis
London Regional Transfusion Committee
Women with anti-c
• How often should you test during pregnancy?
– Every 4 weeks until 28 weeks gestation then every
2 weeks until delivery
• What testing should be done?
– Maternal Rh phenotyping
– Anti-c quantitation (every maternal sample)
– Partner Rh phenotyping
• Refer patient to Obstetric team
London Regional Transfusion Committee
Concentration of Anti-c
• What levels of anti-c are significant?
Anti-c Level
HDN?
<7.5 iu/mL
Unlikely
7.5-20 iu/mL
Moderate risk
>20 iu/mL
High risk of sever HDN
London Regional Transfusion Committee
Women with anti-K
• How often should you test during pregnancy?
– Every 4 weeks until 28 weeks gestation then every
2 weeks until delivery
• What testing should be done?
– Maternal Kell phenotyping
– Anti-K Titre (every maternal sample)
– Partner Kell phenotyping
• Refer patient to Obstetric team
London Regional Transfusion Committee
Women with other red cell antibodies
• Anti-C, -E, -Fya and –Jka are other antibodies
most associated with HDN
• Other blood group antibodies have been
implicated in HND
London Regional Transfusion Committee
Women with other red cell antibodies
• How often should you test during pregnancy?
– Booking and 28 weeks
• What testing should be done?
– Antibody investigation
– Maternal phenotyping
– Titre the antibody against previous sample
– Partner phenotyping
• Refer patient to Obstetric team
London Regional Transfusion Committee
Paternal Testing
• Why do it?
– Helps predict the likelihood of the foetus carrying
the relevant red cell antigen
– For example. Maternal phenotype c- and anti-c
detected. Paternal phenotype Cc. Foetus has 50%
change of carrying antigen.
• Caution – is the partner the father?
London Regional Transfusion Committee
Foetal Genotyping
• When should you send samples?
– When a clinically significant antibody of high concentration
is present
– Women has history of HDN and father is heterozygous for
relevant antigen
• What antigen(s) can be determined?
–
–
–
–
D
c
K
(E)
London Regional Transfusion Committee
At Delivery – D negative women with
no immune anti-D
• What samples are required?
– Maternal and Cord blood
• What tests should be done?
– ABO and Rh typing on both samples
– FMH estimation (flow cytometry / Kleihauer)
– DAT?
• When do you give anti-D prophylaxis?
– When baby is RhD positive
London Regional Transfusion Committee
Future Developments
• Mass testing for foetal blood group antenatal
for RhD negative women
• If done before 28 weeks it would prevent the
use of anti-D prophylaxis in women carrying
RhD negative foetus’s
London Regional Transfusion Committee
Acknowledgement
• This educational resource has been produced to
support education and training by the London RTC
Education Resource group.
• Please acknowledge the working group when using
or adapting this presentation during delivery.
• Please contact the RTC Education Resource group if
you have ideas for other presentations or would like
to be involved.
• Thank you