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I was wanting to get input on DAT's performed for Transfusion Reaction Investigations. Do you perform them with just IgG, C3d or both? TIA.

Hi all, Do you check microscopic reaction for all DAT? Do you use Ortho/Immucor/Other reagent? Do you receive specimen fro API/CAP for proficiency testing? Is there a requirement to check microscopic reaction / mixfield reaction? If yes, is this CAP/AABB/CLIA/other? \ Thanks

Our facility is evaluating making a change to our process for Weak D testing for patients with a positive DAT. For years, if we were required to do a Weak D, but the patient had a positive DAT, we used to cancel the Weak D as invalid. Another hospital in our system mentioned that they tended to perform the Weak D, but then only cancel as invalid if the Weak D is positive. We are thinking about changing to this process, as we now have to result many babies as "Rh Unknown" and give their mothers Rhogam. Per our Anti-D's package insert: "Red blood cells coated with alloantibodies or autoantibodies of the same or similar specificity as the reagent (i.e. cells that are DAT positive) may give weak reactions. This is due to decreased availability of antigen sites because of antigen blocking or steric hinderance. In extreme cases false-negative results may occur." I'm worried about the "extreme cases" where a false negative could occur, but I cannot see this being common. Also, would you think that if the cells were coated with that much antibody, that we would see any other odd reactivity in the ABO/Rh? What do other facilities do? Thank you in advance, Susan

I am sorry if this has been discussed previous... I searched and didn't find anything. Quick question... We are transfusion service that performs DAT's using poly-clonal IgG... if it is positive, we run the mono-clonal IgG, however, we do not run the C3d. How many of you would and/or do run the complement control cells for DAT QC in addition to Check Cells?

Hi All, I have a question, but firstly good old story time for some context. I came across a patient who had positive antibody screen on all three screening cells used (BioRad). I was concerned this may be an auto and pan-reactive, and required units. Performed a monospecific DAT, showing a positive reaction to IgG only. By this time antibody panel finished cooking and showed the patient may have anti-Fya , but couldn't do phenotype. By this time I was nearing my shift so handed it over to my colleague and asked for some units to be crossmatched. However, he refused as DAT was positive and said he rather send the sample to reference laboratory for them to crossmatch. The next day I crossmatched units to verify if it could have been done in our laboratory (just because I am sad that way), and turn out the unit I crossmatched was compatible (which I wasn't surprised about) Question Why does positive DAT (or the cause of positive DAT) sometimes interfere with IAT techniques (such as antibody panel and crossmatch) and sometimes it does not? If both use AHG, then wouldn't positive DAT with IgG cause antibody panels shows pan-reactive with red cells? But obviously it doesn't, but I'm trying to figure out why, and I'm sure the answer is quite obvious. My laboratory seems very hesitant whenever they see anything regarding autoantibodies or positive DAT, and thinks that sample cannot be crossmatched in-house and needs to be sent off without even trying to investigate. Hopefully, by me asking this question, I can explain it back to my colleagues (but obviously take all the credit). Cheers in advance, Jermin

Hi All, Its been a while since I came back to this forum, but glad I feel like I have gained a lot more insight. I feel like I'm a bottomless cup. So I come with a question, for which there is not going to be a definitive answer (but with BB, is there ever one?), but hopefully, I would gain a bit of understanding. Background: So, our laboratory has started sending samples to reference laboratory for genotyping of the foetus by FDNA, which is great, since we would figure out the Rh(D) status of the baby (on most occasions) before they are born! So our laboratory has set up a flow chart which basically mentions that you do not need to send cord sample of Rh(D) negative mother if the baby is shown to be Rh(D) positive (or D positive, I am quite wary when trying to talk about Rh group), and only send cord if baby of Rh(D) negative mother if the FDNA shows the baby is Rh(D) negative, just to confirm the accuracy of FDNA. It sounds kinda counterintuitive, but we will soon be just not processing any cord sample for the ones we performed FDNA on. That means no cord Blood Group or DAT on a lot of post-delivery patients. Question: By missing out DAT, we would possibly be missing out on detecting ABO incompatible HDN. How significant do you think it is in the early stages? Is it OK to wait to see if the patient shows signs of jaundice and for them to send a DCT sample afterwards? Bonus Question: What does your Hospital/Laboratory do in the event of positive DAT on cord sample, and why do you do it? I had a read through one of the articles stating about the significant of DAT, but they called the Rh blood group as Rhesus, so I'm not going to take them too seriously Cheers, Jermin

Has anyone used this card? What did you think of it? I know it's not available in the US yet, but I'm looking forward to it.

Our facility has decided to start running IgG DATs on our echo (for cords and investigation of warm autos) but there is one snag in the road - neither CAP or API offer an Automated DAT survey at this time - so what do other facilities do? We have a couple ideas but would love to hear what others are doing to stay proficient if running DATs on any automation... 1. Old school blind comparison? - procure blind samples from another facility near by that performs DATs on automation 2. Use the samples from the J (manual) CAP survey on the instrument - but how to report it out on the survey??? 3. Other suggestions????

I run the Provue with the polyspecific DAT card. We only run an IgG control on this. I think I want to transition to the card that does IgG and Complement separately. What control cells do everyone use for the anti-complement gel testing? Brands and such, I mean, I know how to run them.

We had a dialysis patient this morning with a positive antibody screen and a negative panel except that auto control was positive. The DAT was positive with the polyspecifc reagent and anti-IgG but negative with complement. My co-worker mentioned that 'back when we did auto-controls on everybody' that we frequently saw positive autos with dialysis patients. I've never heard of this. Has anyone else? If so, what is the cause? Thanks!

A patient came to the ICU with Hb at 52. It was quickly concluded that he had some sort of hemolytic anemia. He also had an immunodeficiency since birth with low levels of both IgG and IgA, and was wholly uncapable of producing IgM. The doctor requested a monospecific DAT and a screen, and ordered 2 bags of blood. All my lab tests came out as 3+ straight over, including the ctl well, so I proceeded with an antibody identification. Unsurprisingly, the patient's plasma gave 3+ reactions against all panel cells as well as his own rbc's, both with IAT/LISS (gel) and PEG. Autoadsorption x2 gave no other outcome, not even the slightest reduction of reactions. I cross-matched blood (again, 3+ reactions) which the patient received without any reported transfusion reactions. When I had the results from the cold ab panel on NaCl gel cards it clearly showed an anti-e at all temperatures (4, 20 and 37°C). Since the panel is used to identify IgM antibodies I assume that this is an autoantibody of IgM-type, and not a regular IgG anti-e, possibly caused by the IVIg the patient has received? I have no clue. The hospital where I work isn't very large and we don't do any advanced ab identifications ourselves, neither do we encounter these kinds of results and patients regularly. Is there anybody who has some ideas and would like to enlighten me? Would you have done any further investigation regarding ab detection?

Dear All Can I pick your brain about something. Under the UK Guidelines, there is no requirement to perform a post-partum antibody screen on the mother, and no requirement to perform a DAT on the baby if the mother had no antibodies during her pregnancy (or in the past), and the mother was given routine anti-D immunoglobulin prophylaxis during her pregnancy. We are introducing RAADP in The National Maternity Hospital this year and we are wondering how did labs in the UK approach dropping the DAT on the cord. We use BioRAD 6 well ID-Cards (DiaClon ABO/D + DAT): A, B, DVI-, DVI-, ctl, DAT As we sometimes (not often) see one D well negative and the other D well positive we would prefer to stick to the 2 D well ID-card. Our problem is that we cannot source a BioRAD ID-card that has this minus the DAT well. What do BioRAD users in the UK do? Any advice would be greatly appreciated. Best wishes John

When evaluating a specimen for DAT testing, our practise has been to accept a specimen up to 24 hours old, refrigerated if not tested within a couple of hours of collection is preferred. Some of us have been taught that older specs may yield a false positive or a false negative; others just a false positive. We would like to clarify our procedure. I would appreciate any guidance on specimen age and impact on DAT results. What is your practise? Can you point me to any references? Thanks!

What are other Blood banks doing about Complement check cell being unavailable. Are you not testing for complement or are you using a home made control?