Patient had a Type and Screen(TS) done in June 2011 by A Reference Lab. ABSC was negative, ABORH=AB negative. Patient given RhIG on 8/10 by Doctor's office. TS done on by us on 8/26 gave 4+ reactions in gel for both screen cells. Titer was 1:32, Fetal Screen was negative on 8/28. Per AABB Technical manual 17th edition "Administration of RhIG during pregnancy may produce a positive antibody screen in the mother, but the titer is rarely greater than 4."

Is this Anti-D or Passively Acquired D?

Thanks for your anticipated response!

No way of knowing for the next few months. The RhIG anti-D will go away in a few months, maybe up to 6 months. If the patient developed her own anti-D it will still be there well past 6 months.

Do you use gel? Titer will be greater in gel vs tube. When I am in doubt I recommend repeat TS 3-4 months after last dose of RhIg.

Thanks you David and John for your responses.Titer was done in Tube.

I did reccommend that the patient be given postpartum RhIG and

I will also reccommend that a TS be repeated in the future (3-6 months).

Thanks a million!

How much anti-D immunoglobulin do you give?

A titre of 32 sounds high to me.

Malcolm, the other question should also be, did you do a saline titer or was some form of enhancement involved? Enhancement will, of course, inflate the titer value rendering it useless for this discussion.

Very true John.

300 ug of RhIG was given. We always perform saline titers. We have never used enhancement

for any of our titers. (well I haven't and hopefully the MT who performed the titer did not since we

do not have a SOP for this ) :disbelief

Edited August 31, 201113 yr by SRTECH
incomplete post

Even 4+ reaction in gel is kind of strong for RHIG. Sometime we get a specimen after giving full dose of RhIg (very next day) and I haven't seen reaction stronger than 2+ (rarely 3+) in gel.

This may be allo anti-D, considering titer of 32 or may be patient developed allo anti-D and RHiG was given so titer is elevated...

Even 4+ reaction in gel is kind of strong for RHIG. Sometime we get a specimen after giving full dose of RhIg (very next day) and I haven't seen reaction stronger than 2+ (rarely 3+) in gel.

This may be allo anti-D, considering titer of 32 or may be patient developed allo anti-D and RHiG was given so titer is elevated...

I totally agree.

Hi all-I have a related question but not titers- do you perform AHG crossmatching for these patients if need transfusion until anti-D no longer present (if passive)? We have a big debate here about that....

We have a doc who's been notorious for giving RhIG a couple weeks prior to patient's due date and subsequent delivery. We have encountered 4+ rxns (tube) in these folks with previous negative ab screens. However we have never titered them out and attributed the reactivity to the RhIg. We have seen some of the same patients again at a later time with negative ab screens, so from our experience I'd say it is possible. I can not give you specific numbers though, just my recollections.

And in answer to your question Shelby56, we indeed perform AHG crossmatchs.

Edited September 1, 201113 yr by jbrun

Several years ago I noted an increase in the strength of RhIg tested post injection. I wondered at the time if the RhIg formulation had been changed, but I was never able to confirm that. We see stronger reactions, higher titers, and longer half life than we used to see.This all occurred without a change in our techniques.

To Shelby56: we do AHG crossmatches on any patient with a passively acquired antibody until the antibody is no longer detectable.

I wonder if patient got more than 1 injection of Rhig? You did the right thing by giving a dose of Rhig postpartum. When in doubt, give the Rhig.

I wonder how high a titer could get if they gave more than one dose of RhIG over a few weeks. It does seem suspicious for allo anti-D.