YorkshireExile

Few days ago we had the following patient: 5 day old baby due for cardiac surgery. Mother was group B Positive with antibody screen negative. Baby is group O Positive with DAT positive - IgG 3+, (IgG1 1+), C3d 2+, three cell Biorad antibody screen all positive, and eluate showed pan-agglutination. Reverse grouping on the baby 2+ using liss/coombs cards with A1 and B-cells, and at room temp A1-cells: weak positive, B-cells: Negative. We crossmatched a few units and all were 2+ incompatible. A transfusion actually took place with one of the units, with no transfusion reactions reported. So what caused the positive results for the baby? Our head of department wants to send the sample to a reference lab to investigate if there is an antibody to a high incidence antigen. Is that worthwhile? Could that be a possibility? If this was an adult I would just say it was a warm autoantibody, but for a baby.....? We actually found a paper that describes a rare case of apparent in utero RBC autoantibody development. Is that what is happening in this case? Any insights greatfully received!

Thank you Carolyn for the downloads. I would like to ask why do you irradiate FFP and cryo for your neonates? Does anyone else do this?

Would you always do an eluate in the following scenario? Mother is group O Pos, antibody screen negative at delivery. Baby is group A Pos (or group B ) DAT positive. Do you have to do an eluate to prove the antibody causing the Positive DAT is maternal anti-A or anti-B and not a rare antibody that wasn`t detected when the mother had her screen done? Or can you just state the DAT is positive probably due to maternal anti-A (or anti-B ) In my hospital we do eluates for all cases like these, and I think we are wasting our time.

This is from the British Committee for Standards in Haematology: "Maternal samples for confirmatory ABO and Rh D type and FMH testing should be collected after sufficient time has elapsed for any FMH to be dispersed in the maternal circulation. A period of 30–45min is considered adequate (Mollison et al., 1997) and the samples should ideally be taken within 2h of delivery primarily to ensure that the sample is taken prior to woman’s discharge from the hospital (RCOG, 2011)." Ref: TRANSFUSION MEDICINE, 2014, 24, 8 - 20

Malcolm - For the antibody titre methodology in the UK when using the gel cards, do you dilute the plasma in phosphate-buffered saline or in 0.9% Normal Saline? Does it actually matter?

Great topic! We have had temperature charts not put in correctly so the temp is reading 7, but the techs who check the chart daily don`t seem to notice and put the temp down as 3 or 4. My recent favourite - we send blood for irradiation to a nearby hospital. One day we received a call from said hospital asking why we had sent an empty box, what is going on. The tech had sent the box but forgot to put the blood in!

Thank you for your excellent answer Malcolm. So this "competition" can still be going on even if the baby is almost four months old?

Just had this recent case in our place. 3.5 month old baby. Mother B Pos. When baby born, had mixed field reaction (using Biorad/Diamed gel cards) with anti-B, strong 4+ reaction with anti-A. DAT negative. Resulted group as undetermined but assumed it might be due to maternal B cells through a fetomaternal haemorrhage. Asked for new specimen after one week to check but one never came. Baby just come back into our hospital at 3.5 months old. Grouping card is showing strong agglutination with anti-A at 4+, as before. But the agglutination is showing very slight mixed field still with the anti-B (maybe 95% to 5% at a guess). The baby was transfused elsewhere with group O blood, last transfused about eleven weeks ago. Also had group A platelets transfused, last time also about ten weeks ago. So the question is, what is causing the slight mixed field with the anti-B? Can`t be the group O transfused cells, or the anti-A would have a mixed field as well. Surely it can`t be from the maternal B cells after all this time? Is it safe to call the baby group AB now? Any suggestions? Thanks.

Had a question thrown at me the other day and not sure of the answer. What is the rationale behind having the date of the collection written on a blood bank sample for Type and Screen or Crossmatching. We do this in our hospital but do we really need to? The label that goes on our samples has an accession number with the day number of the year eg a sample collected on February 1st would be day 32 on the label. When AABB and CAP says the sample must be labelled with the date of collection, do they mean it has to be hand-written or is the day number on the accession number label acceptable? If it has to be hand-written, why? This information is captured in the computer system. Thanks.

Thank you all for your posts on this topic. I also have the Comprehensive Transfusion Medicine Survey so that will meet all our manual testing needs for CAP. For the automated survey I will do as Kirkaw and aakupaku say and report only the groups and screens as they are our only automated tests.

We are new to CAP surveys and this is my first transfusion one. We`ve been sent the automated survey JAT-B 2012. This asks for group,screening, crossmatching and antibody ID. The problem is that we only do automated blood group and antibody screens. All our crossmatching and antibody ID is done manually. So what do I do with the CAP survey? Do I just leave those sections blank? Or do I put some sort of code in that explains these tests are not automated? Any help greatly appreciated!

Yes indeed Liz. And that scenario would be an interesting one to explain to our infection control people if it ever happened!

We have blood bags returned from our NICU department. Reasoning is that unfortunately the neonates there are prone to infections and our infection control people always like to implicate the blood units in causing the infection. So we keep the bags (which always contain some blood) for 48 hours post-transfusion in case the neonate does develop an infection, and if that happens then we send the bag for culture. So is this a fair reason for returning the bags? I think not, as we have never had a bag that has shown to have a bacterial infection, and we have been doing this for a long time now. The infection rate in our NICU is probably due to the chronic overcrowding and nursing shortage that occurs there, but blaming the blood unit first is easier to do than to solve these problems. We will go for CAP inspection in December - will they criticise me for keeping these bags in the Blood Bank?

Many thanks Liz - we all like the one in red!

We are having a lab week soon and I`ve been asked to come up with a snappy one-line slogan for the event. At the moment all I can think of is the very lame "The lab - the heart of modern healthcare". Surely someone has a better idea than my feeble attempt - please!!

We are a maternity hospital and currently we perform all our in-patient and outpatient antibody screens using the Diamed (Biorad) Gel Liss/Coombs cards. These cards contain Anti-IgG and Anti-C3d. Bearing in mind my patient population, my question is do I really need to use cards with Anti-C3d or can I just use cards with Anti-IgG only? Antibodies detectable only by their ability to bind complement are quite rare, and I suppose in "normal" maternal patients they are rarer still. We don`t do an auto as a routine with our antibody screening, although if all three of my screening cells were positive I would include a monospecific DAT in the workup along with my antibody investigation. If anti-C3d was present hopefully I would discover it eventually. What do other hospitals (maternity or otherwise) use for their routine screens? Is there a compelling reason why I should stick with my Anti-IgG + C3d cards or could I safely use the (cheaper ) IgG cards only?

So has anyone ever had this scenario in a routine hospital blood bank? A mother with a known antibody but an elution on a baby turns up a different antibody? I know Malcolm will probably have seen this in the ref lab, but I wonder how many times. Anyway, our reporting has now been officially amended to say: DAT Positive PROBABLY due to maternal anti-K. That should keep the accreditation inspectors from my door. I still won`t do elution though. As a large maternity hospital I would be doing 5-10 a day if I did. By the way, UK lottery on Wednesday 7th March. Winning numbers are 2.8.10.19.26.36. You heard it here first!

But I do really know. In my example, if mother and baby are same group, what else could it be but an antibody, anti-K, from the mother? I think it`s a waste of time, money and reagents to do an elution in these cases.

For a cord , if mums screen is positive, is there any need to do an elution still? Surely the antibody that is causing the DAT to be positive is the one that came from the mother. So if the mother has anti-K, then just report as DAT pos due to maternal anti-K. That`s what we do anyway.

We are a large maternity hospital in the UAE and for the last couple of years we routinely give K negative blood to our ladies. On average we have 1-2 cases per year of HDFN caused by anti-K. The last one required numerous top-up transfusions.

Thanks to everyone for their SOPs........ off now to update and improve mine!

Malcolm, From Diamed, we use "ID-Anti-D for confirmation of D variants by IAT" - to quote the manufacturers instruction title. To further quote - "This can be performed using a monoclonal anti-D formulated to detect weak D`s and DVI on the ID-card coombs anti-IgG." We use this reagent for confirmation when our cord blood groups are Rh negative. Is this equivalent to "anti-weak D", or are Diamed using marketing terminology falsely!

I think the docs were just looking for an excuse as to why the baby had some problems during the exchange. Easy to blame the blood bank rather than their technique or the babies existing medical problems. By the way, isn`t the pH of CPD 5.3-5.9? (AABB 16th edition). P.S. Sorry about the small font on my first post. Don`t know how to correct it. Hope people can still read it.

One of our neonatal consultants came to me today asking about pH of blood for exchange transfusion. We had an exchange transfusion a couple of days ago and our unit preparation is as follows: We get a fresh unit (less than 5 days old) of CPD-SagM packed cells, then spin it down in the centrifuge to remove the supernatant containing mannitol. We then reconstitute with AB plasma to get a HCT of approx 45%. The unit in this case was used about 45 minutes after preparation . The birth weight was 1.28kg, and the reason for the exchange (as far as I know) was a high total bilirubin of 26.2 umol/L and during the exchange procedure there were some complications (I think due to cardiac arrhythmia) but the baby was okay eventually. For some reason they took the pH of the unit before starting the exchange(is this a common thing to do?) and it was 6.7-6.8. The consultant was concerned that the pH value might have contributed to the exchange transfusion problems due to acidosis and lactic acid build-up which the neonate was unable to compensate for due to its prematurity. So his general questions are : Should they always test the pH of a unit before they do exchange transfusion? Is there a cut-off where the unit is unsuitable to use because of the pH value? Would a pH of 6.7-6.8 for an exchange transfusion unit have any consequences concerning the babies metabolic state? I`ve searched literature concerning this topic but couldn`t find anything. I would probably just advise the consultant that these units are okay and for the babies parameters to be monitored and modified accordingly.

We have the same "problems" as ElinF. We use gel and don`t do weak D testing on our prenatal patients, but if my gel reaction shows 1-3+ positivity I`m obliged to report it as RhD positive. I then put a result comment in stating that the patient is actually a weak RhD positive. If there is a discrepancy with the historical group being Rh Negative, I then have to explain that as well. Unfortunately with my wonderful(!) Cerner Millenium computer system I cannot actually report the group initially as Weak D positive, so I have to put the comment. If these patients required blood I would try to give them Rh Negative blood to be on the safe side.