Mabel Adams

For IgG or polyspecific I was taught 2+ or greater a jillion years ago. Complement is less although the Quotient complement coated cells react the best I have seen.

I was thinking of a benchtop one but is there an advantage to this one? Did you buy it straight from Hettich or another supplier?

I think Siwa's is the first that is immediate spin. The others are monoclonal but must be tested at the AHG phase I believe. Please correct me if I am wrong. I would love to have choices for this purchase.

Or if you wanted to teach in an MLT/MLS program at a community college or university.

I remember John Judd once advising me to titrate an anti-M suspected to have an IgG fraction and not worry about separating the IgG from the IgM unless the titer became significant. Then we could titrate it after destroying the IgM if need be to see what the true IgG titer was. It never exceeded something like 8 so we never had to send it out for additional testing. These seems something like that--drawing a line of what is safe to save the cost of extra testing. Only do the additional testing when it is no longer safe to avoid it. You would have to determine how you will turn it out so as to not overly confuse the OB/perinatologist. "Titer against c, E, Fya, Jkb and S positive cell = 8"? Then next time when it is 16 with a cell of that phenotype, you would repeat separate titrations and results would be "titer against c & E positive cell = 8 & titer against Fya, Jkb and S positive cell = 4"? Or do you then go to separate cells for all of them but the E & c? Or turn it out as 16 and they quit using titers to monitor? I can see some logic to moving to ultrasound monitoring as soon as the cumulative titer is above 16 or so but we also like to watch how titers change over time to help us guess which antigens baby is positive for. If you already tested amniocytes for antigens that would be moot but if you have only serology to go on you could miss some clues. We titrate E & c together because they are likely to be inherited together and separate E+, c- cells are hard to find. It also depends on if you can reliably find the same phenotype of cells for the next titration (we don't have the perfect world of using the same specific donor cell for the entire pregnancy). Maybe it also matters if you know dad's phenotype/genotype. If he is R2r then baby could be c+ E- but not if he is R2R2. Sorry to ramble on; surely someone with more experience in this than I can answer with something more substantive but I've enjoyed speculating.

We called the screen positive (went ahead and reported the gel screen) because we wanted the computer to prevent electronic crossmatch if they wanted more blood while that specimen was still good on a later shift that hadn't heard about her and didn't read her comments. We were giving her units negative for the 2 antigens that she lacked (good thing that she was heterozygous for most of our "usual suspects") so we didn't want random units to be issued inadvertently. Also, I read that patients on these drugs sometimes have a drop in H&H at first dosing so I wasn't really willing to go out on a limb and call them compatible and imply that they would have normal red cell survival.

If I need to buy a new refrigerated centrifuge for spinning down units (packing whole blood, removing preservative solution for baby exchanges etc.) does anyone have any recommendations? I want the smallest size that will do the job since we aren't a blood center. The one vendor I looked at does not list blood products as one of the functions they sell accessories for.

I have a somewhat related question and would love your (and anyone else's) input. Do you have a good system for documenting annual thermometer calibration? We have a lot of thermometers and, over the year, some get moved or broken, so I am trying to find a good way to keep track of where they are and which are due and document their calibration.

Thanks for the heads up. Now if only we could get someone to tell us or tell the patient to tell us that they are on these drugs. If you have any "pull" with someone in Seattle, feel free to pass along the request.

We just got our first anti-CD47 out here in the sticks on a patient who went to Seattle for a clinical trial. That drug is Hu5F9-G4. No other name yet. It interfered with her reverse as well as all gel testing. We did a 30 minute saline screen and it was 4+ at 37C but negative at IAT using Immucor's anti-IgG which doesn't react with IgG4. She was antigen typed before starting treatment so we got that information and gave her K and Fya negative units (lucky she is positive for most antigens). We called them incompatible because we have not validated the Immucor anti-IgG as our test of record, the screen was 4+ at 37C and because the drug causes the patient's H&H to drop so I wasn't sure that the units would be certain to have normal survival. I didn't expect to get one of these for a few more years since we aren't in a big teaching hospital region. It would have been nice if the big center had sent her home with information that she was on this and instructions to tell the blood bank. We lucked out finding clues in Epic's Care Everywhere so we called the Seattle blood bank.

We have found that not adding enough buffer will cause false positives, especially in gel testing. I say to add an extra drop or two after they already think it is blue enough to be sure.

Thanks for the link to the guideline. When it mentions free fetal DNA is that available in the UK from peripheral blood from mom or is that done on amniotic fluid? I don't think any testing but D is available in the US from the mom's blood sample.

What are you all using as "significant" titers for antibodies to Rh, Duffy and K antigens? I had an old reference that said to use 64 for anti-Fya, 8 for anti-K and we usually use 16 for Rh (all tube testing). I see newer references suggesting using the same for anti-Fya as for Rh so thought I would check with this group for current practice/recommendations.

We used to do weak D tests with post-partum RhIG workups because we did a full blood type and antibody screen with them to make sure mom was a candidate. (Also, to look for massive FMH that would cause an Rh neg mom to look like a weak D but that was before the Fetal Screen/rosette test was invented.) In those days, weak D pos moms were not RhIG candidates, but they are now. With modern reagents, those who react only at AHG anti-D testing are likely to be partial D VI and more likely to make an anti-D. We would rather not find them and just call them Rh negative from the IS test so we don't do weak D testing routinely on obstetric patients. We all dropped the antibody screen when we started using sensitive techniques like gel that picked up the 28 week RhIG dose at the time of delivery. If the screen was negative, you gave RhIG; if the screen was positive with anti-D (unless it was super strong) you still gave RhIG so why do the test if it won't change the treatment? Now we do weak D tests only if the Fetal Screen is "diffusely positive" to understand if a weak D is causing it. We get surprisingly few of them. Of course we do weak D tests on the babies of Rh neg moms.

There was an article in Transfusion a few years ago. I think the research came out of Pennsylvania. Sorry, can't find the reference at the moment. Mayo has a powerpoint called Emergent Use of Group A Thawed Plasma that I hope is still at this link. MayoMedicalLaboratories.com/hot-topics