Leaderboard

Okay, I'll try! It is very unusual (although not unknown) for a baby to make either anti-A or anti-B at birth, as the immune system is generally too immature to produce such antibodies. It is virtually unknown for a baby to make either an auto-anti-A or an auto-anti-B (it is incredibly rare for an adult to do this, let alone a baby), and a baby certainly will not produce any IgG antibodies. If a baby is suffering from HDFN due to ABO, the antibody must, therefore, have been derived from the mother1. For the mother's antibodies to transfer from her circulation to the foetal circulation, the antibody has to be IgG in structure (IgM will not cross the placenta). So, if the baby is suffering from ABO HDN, the baby's red cells must be coated (sensitised) with maternal IgG ABO antibodies. If the baby's sample is put at 4oC (put in a fridge) overnight, when it is examined the next morning, by tipping the sample, agglutination can be seen (usually macroscopically), and this can only be due to maternal ABO IgG antibodies. In Addition, a paper by Voak et al2 spoke about anti-A IgG antibodies causing agglutination. Is this because the ABO antigen is close to the end of the carrier molecule (like M is near the end of glycophorin A)? Well, certainly the N-acetyl-D- galactose molecule that makes up the A antigen (and the D-galactose molecule that makes up the B antigen), is found at the end of the oligosaccharide molecule upon which the ABO antigens are found, but, in addition, there are some 250, 000 and 370, 000 A antigens expressed per red cell (although there are some 800, 000 GPA sites per red cell3). The site of the ABO antigens are, therefore, likely to be important. References: 1. Klein HG, Anstee DJ. Mollison's Blood Transfusion in Clinical Medicine. 12th edition, 2014, Wiley Blackwell, chapters four and twelve. 2. Voak D, Abu-Sin AY, Downie DM. Observations on the thermal optimum, saline agglutinating activity and partial neutralization characteristics of IgG anti-A antibodies. Vox Sanguinis 1973; 24: 246-257. DOI 10.1111/j.1423-0410.1973.tb02636.x. 3. Reid ME, Lomas-Francis C, Olsson ML. The Blood Group Antigen FactsBook. 3rd edition, 2012, Academic Press, page 62. I hope that helps, even if it doesn't win me the bonus points!!!!!!!!

We do the screen and the panel right away if there is enough eluate to go around, however our policy also states that if the DAT results have not changed from previous time and no new antibodies have formed, an eluate does not need to be performed. We have a lot of cancer patients on weird meds that mess with the DAT so it would be a supreme waste of reagent to do it over and over to achieve the same "All cells reacting, no specificity" results.

Rhetorical question: Is it a typical request for a "Type & Panel" ? If you are almost certain that the eluate will be reactive, I agree that the screen may be redundant. However, it is still a test against phenoptyped cells and the information is still valuable even if you end up testing a panel.

One could argue that by doing the panel first you are being efficient and potentially saving time with antibody identification if something is detected. But by doing the screen you are saving reagent/cost. I'm not sure there is a right or wrong answer to this question?

And just a practical tip. Best way to detect most anti-M is in an IAT with incubation at 20°C rather than 37°C. No references for this, just lots of practical experience

cross trained, it is so hard for everyone.

"I'm happy if my techs just get the right day of the week and AM or PM." Ain't that the truth!

Cool. Crossing it off my list of things to care about!

Terri no doubt has an elegant solution involving packing foam, but have you called Helmer? Their tech support is very good. I'm not aware that the scribes can be adjusted but you never know...Short of that, you could replace the scribe, readjust it every morning (you're probably looking at it daily anyway), or learn to live with it. An hour is not much of a space on that little disc; I'm happy if my techs just get the right day of the week and AM or PM. The purpose, beyond satisfying AABB and CAP, is redundancy to your alarm system to see if your blood got cooked while no one was looking, and to see if an unfamiliar tracing might indicate a potential problem down the road. The batteries, by the way, are only for backup with a power loss and shouldn't have anything to do with normal operation.