Hello All!   I took over as supervisor not too long ago.  I am in the process of updating policies and procedures that have just got to go.  One such thing is doing full panels on OB patients who have recently been given Rhogam.  We did 122 such panels last year and they are a waste of time IMO.   Do you guys have a separate policy for this or do you include it in your general AB ID policy?   Do you still do full crossmatches for these patients and what do you call it in the computer.  Right now they are calling them Passive anti-D.  Does anyone have a policy or tips they are willing to share? 

 

 

Thanks!

  I included this as part of my ABID policy. If the patient has received Rhogam, we only do the cells with @ in the Ortho panel. We use to call it a Rhogam-D in our old computer system but now it is called a Passive D since that was what was built in the system. We don't require a full crossmatch since it isn't a true antibody.

   I hope this answered all your questions.

Do you do an ab screen with every RhIg order?  It is not necessary for post delivery specimens.  I finally got my OB guys to not worry about an absc with an RhIg workup and it decreased my screens considerably.

Yes, we do.  Many of our patients don't have any prenatal work on file with us and we do not do TYSC upon admission to L&D.  We also do not offer outpatient Rhogam so sometimes we don't know exactly when a patient recieved rhogam (if it isn't in the patients chart and if it is not during the patients physicians office hours).   Do your patients typically have prenatal work on file at your facility?  Thanks!

We do a "short panel" (the @ on Ortho panels or [ ] on Immucor panels), call it passive anti-D probably from RhIG.  We do not require AHG XM.

Edited May 6, 201510 yr by CMCDCHI

I'm with David on this one.  We stopped doing antibody screens on OB patients for RhIG workups especially where our records indicated a negative screen prior to the antenatal RhIG injection.  :clap:That sure made my staff happy.

Edited April 26, 201510 yr by John C. Staley

We get a Type and Screen prior to delivery. We do mini panels as well but right now our LIS is set up to consider "anti-D due to RhIg" clinically significant and prevent electronic XM. I'm of the mind that we should change that but I seem to have an endless to-do list.

Our OB docs don't routinely order a T&S  but...

If we have to do an antibody ID for a patient that has had rhogam we put it on the provue and run the 11 cell. It's easier that way. I've set up Meditech with an antibody called anti D post Rhig to differentiate a real anti D.

also, all of our patients receive their antenatal Rhig at one of our facilities so we do have a a record of it in their BB history.

We also do the @ cells on the Ortho panel and do not do AHG crossmatches.

We no longer to antibody screens - the reasoning is that a positive baby would result in more rhogam anyway and the chances of a non-D antibody being picked up --that wasn't already picked up at 28 weeks-- is extremely slim. Plus they will be discovered at booking next time anyway... A lot of work for nothing!

We perform Type & Screens on OB patients.  If the antibody screen is positive on an Rh Negative OB patient with a RhIG administration date within the previous 12 weeks, we perform Ortho's short antibody panel.  When performing the short panel a D-antigen positive cell must be run for the positive control.  If the D-antigen positive cell reacts >2+ it must be further investigated for active (alloimmunization) Anti-D.  RhIG does not produce strong reactions and therefore Blood Bank staff must practice caution when "assuming" passive Anti-D due the RhIG administration.  A strong indicator for Techs is the reaction strength noted for the D-antigen positive cell.  Furthermore, reactions >2+ should have an antibody titer performed to aid in interpretation of passive Anti-D versus active Anti-D.  RhIG produces a titer of 1:4 or less.  It would be rare for RhIG to produce a titer greater than 1:4.  Active Anti-D generally produces a much higher titer, therefore distinguishing it from passive Anti-D.  Interpretation issues should involve consultation with the Medical Director or a pathologist.

Does anyone run a 1:4 dilution of the patient's plasma with a D positive cell in gel? If so what do you use as a diluent?  

No!  That will tell you nothing, but may land you in the deep and nasty.  A true alloanti-D will start off as low titre, which may well disappear at dilution of 1 in 4, but will not save you from litigation!

No!  That will tell you nothing, but may land you in the deep and nasty.  A true alloanti-D will start off as low titre, which may well disappear at dilution of 1 in 4, but will not save you from litigation!

 

Thank you. I wanted to post something similiar but didn't feel I had the oomph.

Maybe my post was a little too brief. I was only thinking of testing the 1:4 dilution after performing a screen and testing the selected Ortho cells designated with the @ symbol on a post delivery sample of a mom who has received ante natal Rh Immune globulin since the AABB says that "passively acquired anti-D rarely achieves a titer above 4.

the AABB says that "passively acquired anti-D rarely achieves a titer above 4.

 

I think that guidance was established based on titers performed in saline and not Gel.  As a reference lab, we are a bit conservative and report out (paraphrased) "anti-D demonstrating a titer of less than 4 in saline indicating it may be due to recent administration of RhIG.  To establish this as the sole cause of the antibody, repeat testing six months post delivery should demonstrate a negative antibody screen."

For the original question, we use the ECHO so do a full panel. If we get an anti-D on an OB patient, we call to get a history & they usually ask the patient if & when she got RhIG. It would be difficult to get previous antibody screen results. My computer has either "anti-D due to RhIG" or "anti -D". We interpret anti-D with a comment the patient received RhIG with the date. In the computer resulting "anti-D" requires an AHG crossmatch where "anti-D due to RhIG" is an electronic crossmatch. I would be okay with the above "anti-D post RhIG" & an electronic crossmatch, I just have a problem saying RhIG caused the anti-D. I think I am too picky.

I agree with your "pickiness" mcgouc, and would insert the word "probably".

We do a T&S on all OB's that come in for delivery.  We've had a few to bleed after delivery, so we are set in an emergency.  We have 2 panels built in our LIS for L&D, one for Rh positives and one if they are Rh negative and have received Rhogam.  The Rh negative panel orders the Ortho 5-8 cells.  We result that with a comment, not screened for D along with the date the rhogam given. If the infant has a postive DAT, we do an elution.

What about C, E and K that you are not able to rule homozygously? Most patients that are Rh negative are also C and E negative and there is the possibility of another antibody other than the anti-D due to Rhogam, and in the case of a pregant woman, that could cause a HDFN.

Any thoughts on this?

I would expect an r'r and an r"r to be included in the panel, but if they give negative results, I wouldn't be bothered.

 

You are most unlikely to have access to r'r', r"r" or r_yr_y red cells to rule out with cells expressing homozygosity (and even if you do, are you certain that they are, for example r"/---, to which the answer is, you are not - and yes, I have come across one!), but, in any case, an anti-C or anti-E that is only detectable by the use of such red cells is most unlikely to cause clinically significant HDFN (the antibody usually needs to have a titre of 32 or above).

 

Then, if the antibody has only been made in the third trimester, even if it gets stronger during the pregnancy, the received wisdom (see Mollison) is that the antibody will not cause clinically significant HDFN, or, at most, will cause mild HDN (rather than HDFN).

 

It is extremely rare for an anti-E to cause HDF, rather than HDN, and anti-C causing anything other than mild HDN would deserve a case study write up.

 

Lastly, on the subject of Rh antibodies, there is no way that you could screen for all Rh specificities.  You would be most unlikely to have a screening cell that is, for example Be(a+), and yet anti-Be^a causes very severe HDFN.

 

Turning to anti-K, it is unusual, although not unknown, for anti-K to show dosage.  Again, you would be lucky to have a K+k- screening cell, but the same applies to anti-K made in the third trimester, as applies to the Rh antibodies in the likelihood (or, rather, otherwise) of causing a clinically significant HDFN.

 

To make a long story short then, I wouldn't worry!

Edited November 27, 20159 yr by Malcolm Needs

Does anyone run a 1:4 dilution of the patient's plasma with a D positive cell in gel? If so what do you use as a diluent?  

 

 

No!  That will tell you nothing, but may land you in the deep and nasty.  A true alloanti-D will start off as low titre, which may well disappear at dilution of 1 in 4, but will not save you from litigation!

 

I agree with Malcolm.  We have a pregnant lady who came to us from another town who has an immune anti-D that is reacting very weakly.  The gel antibody screen showed 2+ reactivity and the saline titer was zero with a score of zero as well.  The previous doctor had sent one previous titer that I am aware of and the results were the same.  Hopefully she stays that low, but it will be interesting to follow her to see if it rises.  Our last immune anti-D patient had a significant jump in her titer 1 month prior to delivery, but she started out much higher well.