We have an OB patient in to deliver who typed in gel anti-D as a solid 2+.  Control is neg.  We have typed her 3 times before in recent years using the same methods and she has always tested D negative.  Most recent A Neg type was last November. Now with Albaclone anti-D, she is negative at IS and 37 but 1+ at AHG.  Her prior baby was Rh neg so no attempted fetal screen test then.  This baby is 1+ at IS with the Albaclone anti-D and 3+ at 37C and AHG.  We don't usually run cord blood Rh types in gel. We will recommend the patient be sent for molecular testing.  My question is what would make her D antigen strength change so much (or make Ortho's gel cards change their sensitivity that much)?  I know leukemia can weaken D antigens, but she seems perfectly healthy.  No bone marrow transplants.  No recent transfusions.  No reason to believe she isn't the same patient as before.  I can't find any references besides Issitt mentioning changes in D reaction strength. Issitt mostly mentions the Leukemia aspect, but I feel like I have heard of other situations.  She had shingles in April and was treated with ACYLOVIR for what that's worth.  We are treating her as Rh negative for now.

I don't think this is the reason in the case you describe, particularly in the case of the baby's D typing, but, just to remind people, a monoclonal anti-D taken straight from the fridge, and not allowed to come to room temperature before used for testing, can lead to false positive results.

See Thorpe SJ, Boult CE, Stevenson FK, Scott ML, Sutherland J, Spellerberg MB, Natvig JB, Thompson KM.  Cold agglutinin activity is common among human monoclonal IgM Rh system antibodies using the V4-34 heavy chain variable gene segment.  Transfusion 1997; 37: 1111-1116.  DOI:  10.1046/j.1537-2995.1997.37111298088038.x., and Thorpe SJ, Ball C, Fox B, Thompson KM, Thorpe R, Bristow A.  Anti-D and anti-i activities are inseparable in V4-34-encoded monoclonal  anti-D: the same framework 1 residues are required for both activities.  Transfusion 2008; 48: 930-940.  DOI:  10.1111/j.1537-2995.2007.01624.x.

1 minute ago, Malcolm Needs said:

See Thorpe SJ, Boult CE, Stevenson FK, Scott ML, Sutherland J, Spellerberg MB, Natvig JB, Thompson KM.  Cold agglutinin activity is common among human monoclonal IgM Rh system antibodies using the V4-34 heavy chain variable gene segment.  Transfusion 1997; 37: 1111-1116.  DOI:  10.1046/j.1537-2995.1997.37111298088038.x., and Thorpe SJ, Ball C, Fox B, Thompson KM, Thorpe R, Bristow A.  Anti-D and anti-i activities are inseparable in V4-34-encoded monoclonal  anti-D: the same framework 1 residues are required for both activities.  Transfusion 2008; 48: 930-940.  DOI:  10.1111/j.1537-2995.2007.01624.x.

I am aware of this for the Alba anti-D but never had the reference, so thanks for that.  That reagent, with its potentiators, definitely will pick up i on cord cells and, we suspect, the occasional i adult.  It is worse if it is cold. It disappears at 37C so is pretty obviously not D.  We use it because it has a similar sensitivity for weak D to Ortho gel (usually!!!).

Yes, I didn't think it was directly pertinent to your case Mabel.

I'm sure I know the answer but I have to ask, did you test a second sample drawn at a different time?  I'm sure the 1st thing you did was confirm right patient, right blood but had to ask.  

6 hours ago, John C. Staley said:

I'm sure I know the answer but I have to ask, did you test a second sample drawn at a different time?  I'm sure the 1st thing you did was confirm right patient, right blood but had to ask.  

It's pretty likely it's her blood because baby has a weak D Rh type but, yes, we thought of that.

I've seen anti-D come stronger or weaker in the same patient, and when we've sent them for molecular they come back as some form of weak D usually. We use Immucor reagent here, so tube typing, and it's the same reagents on the instrument as in our tube, but we do see some variability from the two methods, likely because of the RT incubation the instrument does on all blood types. The weaker D can "unbind" it seems, and the instrument will call something Rh negative when in tube we get weakly reactive or 1+. 

She came back as a weak D type 1.  Her second specimen (the one we sent out) typed similarly to the first in tube--neg at IS and 37C but pos at AHG. 

In that case, I think that you would have been justified to have given "straightforward" D Positive blood in terms of a transfusion.  This is based on two papers from experts on the subject.

Sandler SG, Flegel WA, Westhoff CA, Denomme GA, Delany M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD.  It's time to phase in RHD genotyping for patients with a serologic weak D phenotype.  Transfusion 2015; 55: 680-689.  DOI:  10.1111/trf.12941.

Sandler SG, Chen LN, Flegel WA.  Serological weak D phenotypes: a review and guidance for interpreting the RhD blood type using the RHD genotype.  British Journal of Haematology 2017; 179: 10-19.  DOI:  10.1111/bjh.14757.

My own mentor, Joyce Poole told me that Weak D Type 1 individuals rarely produce an anti-D after transfusion with D Positive blood - although she had come across about three or four cases WORLDWIDE!!!!!!

5 hours ago, Malcolm Needs said:

In that case, I think that you would have been justified to have given "straightforward" D Positive blood in terms of a transfusion.  This is based on two papers from experts on the subject.

Sandler SG, Flegel WA, Westhoff CA, Denomme GA, Delany M, Keller MA, Johnson ST, Katz L, Queenan JT, Vassallo RR, Simon CD.  It's time to phase in RHD genotyping for patients with a serologic weak D phenotype.  Transfusion 2015; 55: 680-689.  DOI:  10.1111/trf.12941.

Sandler SG, Chen LN, Flegel WA.  Serological weak D phenotypes: a review and guidance for interpreting the RhD blood type using the RHD genotype.  British Journal of Haematology 2017; 179: 10-19.  DOI:  10.1111/bjh.14757.

My own mentor, Joyce Poole told me that Weak D Type 1 individuals rarely produce an anti-D after transfusion with D Positive blood - although she had come across about three or four cases WORLDWIDE!!!!!!

Can not even Weak D type 1 patients be consistent in their ability to make anti-D?!??!  I still don't know why we got such different results than previously in gel. I verified that Ortho didn't change the anti-D clone in their gel cards between November and now. I guess this patient just wanted to mess with us.

12 hours ago, Mabel Adams said:

Can not even Weak D type 1 patients be consistent in their ability to make anti-D?!??!  I still don't know why we got such different results than previously in gel. I verified that Ortho didn't change the anti-D clone in their gel cards between November and now. I guess this patient just wanted to mess with us.

That's what make the life of a blood banker so interesting!! Who wants to be an accountant where 2+2 always = 4!!!