Red Cell antibodies

Question 1

For which antigens is non invasive fetal genotyping available for now?

Answer 1

DEeCcK

Question 2

For antibodies other than Anti-c, Anti-K and anti-D, what risk factors should prompt referral to fetal medicine?

Answer 2

Previous HDFN
Previous intra uterine transfusion
a titre of 1:32 or above (especially if titre rising)

Question 3

For anti D, what titre level indicates moderate risk of HDFN?

Answer 3

> 4iu/ml to 15 iu/ml

Question 4

For antiD levels what titre level indicates high risk of HDFN?

Answer 4

> 15iu/ml

Question 5

For what Anti D titre level should a fetal medicine referral be made?

Answer 5

> 4iu/ml

Question 6

What are the titre level cut offs indicating moderate and severe risk of HDFN for Anti-c antibodies?

Answer 6

> 7.5iu/ml indicates moderate risk
20iu/ml indicates severe risk
7.5iu/ml prompts fetal medicine referral

Question 7

What is the Anti-K titre cut off for fetal medicine referral?

Answer 7

Once antibody detected always refer as HDFN can occur at low titres

Question 8

Once detected how often should anti D and anti c and anti K levels be monitored in pregnancy>

Answer 8

every 4 weeks until 28/40
every 2 weeks until delivery
This is interestingly the same for Anti K antibodies despite no evidence that titre makes a big difference>

Question 9

For woman not previously affected by HDFN when should retesting occur in pregnancy?

Answer 9

Routine 28/40 antibody assessment

Question 10

What testing is required if titres rise beyond acceptable level?

Answer 10

weekly USS for MCA PSV to assess for anaemia

Question 10

What testing is required if titres rise beyond acceptable level?

Answer 10

weekly USS for MCA PSV to assess for anaemia