In your lab, on Rh negative mothers with Rh positive babies, what testing do you perform with the fetal maternal hemorrhage screen?  Do you perform a repeat ABO/Rh and an antibody screen?

 

Thanks!

 

Catherine

 

 

Rh typing only (no ABO or antibody screen) on a postpartum maternal blood sample. Would do Weak D test on mom if fetalscreen was positive. 

Edited June 16, 201411 yr by Dansket

We would only perform a D/Du test on a mother with a positive fetal screen, preferably on a pre-delivery sample.

Unfortunately we do perform an absc for RhIg.  I have one OB guy who wants it done and one who does not.  I don't have different rules for differnt docs - I have tried having my MedDir talk the one out of this but all he says is "What if they have anti-D?"  WELL MOST OF THEM DO NOW because we use gel.  Does he do a recheck in 3-4 months as suggested - NO!

 

enough said.

We do an antibody ID on the admission type and screen sample if the screen is positive. On the FMH screen we just do a repeat blood type. If the FMH screen is positive, then we test the mom for Weak D.

We do nothing on the mom except the fetal screen test.  If it is grossly or diffusely positive, we will do a weak D test on the mom to see if the Fetal Screen is positive due to a weak D antigen.  We will usually have done the mom's prenatal testing.  

 

I have often wondered why we would check the Rh on the mom we are doing the Fetal Screen on.  If we have her type wrong we will know it when her Fetal Screen comes off positive macroscopically.  All the moms that were determined once early in pregnancy to be Rh positive are the ones at risk if there was a mix-up in that original type and they are really Rh neg.  Those sites that do a blood type on all OB admissions have this covered of course.

For those of you that do not do the antibody screen, did you do one prenatally or have access to the prenatal records to determine that the mom is not alloimmunized?

We have just changed ou policy  - no absc for RhIg distribution.  Fetal Bleed Screen post partum.

In the absence of a reliable method for differentiating allo-immunization versus passive immunization, it is simpler (as does no harm) to identify potential candidates based soley on infant's Rh, mother's Rh and fetalscreen.  I don't believe manufacturers list a postpartum antibody screen as a criteria for Rh Immune Globulin prophylaxis.

Edited July 1, 201411 yr by Dansket

We do only the FMH Screening Test.  (No Antibody Screening.)  If the FMH Test is Positive, we do an Rh typing (and Weak D Test, if necessary) on the mother's specimen.  If the D and the Weak D tests are Negative, we do a Direct Antiglobulin Test on the mother's red cells (to make sure that a Pos DAT is not causing a false positive FMH test.)

 

Donna

No antibody screen. Too many of our mothers had Rhogam at 28 weeks.

ABO/Rh, D^u and fetalscreen.

For those of you that do not do the antibody screen, did you do one prenatally or have access to the prenatal records to determine that the mom is not alloimmunized?

Yes

YES

We do an antibody ID on the admission type and screen sample if the screen is positive. On the FMH screen we just do a repeat blood type. If the FMH screen is positive, then we test the mom for Weak D.

Edited July 24, 201411 yr by ANORRIS

 

Edited July 24, 201411 yr by ANORRIS

I think the fact that the Rh pos baby of this Rh neg mom does not have a positive DAT is evidence that she is not sensitized.  You can argue that, although sensitized, her antibody is too weak to cause a positive DAT but then it will be too weak for us to tell from antenatal RhIG. We must err on the side of caution so that we always give postnatal RhIG whenever it might be needed.