30 April 2022 (Saturday) - Group or Collection

 

I was flipping through Facebook when I came across a discussion on one of the work-related groups. I say “discussion”, it was more of a contest to see who had had the most obscure blood group antibody at the most inconvenient time. These aren’t uncommon… there is always someone who can trump your “Bombay blood with a massive GI bleed”, but a chap I knew mentioned a case of anti-Er(a).

I’d never heard of this one before, and so looked it up.

Like all blood group antigens it is one in a set of antigens of a blood group system…. But it isn’t a blood group system. It is a blood group collection.

This was new to me… Collections are blood group antigens “which are biochemically, genetically or serologically similar where the genetic basis has not yet been discovered”.

It would seem that being a “system” is a step up from being a “collection”. A trivial distinction? Not really. Such nuances are rather important.

One lives and learns….

7 July 2021 (Wednesday) - K-Typing

A very valid reason for doing CPD is to keep up-to-date with current trends and practices. It has to be said they change at breakneck speed in blood transfusion.

Take fresh frozen plasma… When I was a lad the stuff only came in A and AB flavours. There was (supposedly) no need for blood group O FFP. Then the stuff came out, and there was (so it was claimed) no need to look at the labels. Anyone could have FFP of any group. Nowadays giving O FFP to a non O recipient is a “never-event”.
Take single unit transfusions. Back in the day it was widely said that the dangers of a single unit transfusion greatly outweighed the benefits. Nowadays single unit transfusions are the norm. 

But things don’t just change over time. They change from place to place. Here in the UK is it standard practice to make sure that *all* women of childbearing age receive K-negative blood products. That is *all* women without exception !!!

Someone from America posted on the Facebook “Blood Bank Professionals Group” this morning saying that an obstetrician had asked for K-negative blood for his patient. All the UK-based people commented “well so he should”, and all the American-based people laughed.
I suppose the difference is that in the UK pretty much all of the donor blood is K-typed whereas in America the patient would be billed for the typing, but it did bother me somewhat to see posts from American lab people who were saying how easy it is to get K-negative blood for someone with anti-K antibodies (which it is), but at the same time were seemingly oblivious to the dangers of HDFN due to anti-K antibodies.

 

20 November 2020 (Friday) - "Hurts My Kidneys" (!)

I know this is (probably) ridiculous but… we have a patient on long-term transfusion support. He is B Rh(D) Pos Rh(E) Neg with allo anti-E in his plasma. We’ve been supplying crossmatched ABO compatible (i.e. O or B) Rh(E) Neg K Neg for some time. The chap is reasonably educated and understands more about blood group serology than the average patient.

However…

Today he has asked if we could supply only B blood. He is not bothered about the Rh(D) Pos or Rh(D) Neg bit and he understands that each unit is crossmatched, but he is insistent that O blood gives him a pain in his kidneys. Not a “proper” measurable-in-any-way reaction, but just causes pain.

I posted onto the Facebook Blood Bank Interest Group to see if anyone else had experienced this, and whether it might just actually not be nonsensical. You can see the thread by clicking here. High titre anti-B, anti-HI… there might just be something in what the patient was saying (but we doubt it…)

7 July 2020 (Tuesday) - Anti-M and Dosage

An interesting case today – positive antibody screen by capture. The enzyme panel was clearly negative but panels by IAT and capture were 3+ in some cells and clearly negative in others. At first sight it seemed they seemed inconclusive, but on closer inspection the positive reactions were all with cells that were homozygous for M. In the negative reactions the M was either in the heterozygous or was absent.
I’ve seen this sort of anti-M before. The word is "dosage".. but I don’t know/can’t remember why it doesn’t react at all with the heterozygous cells. I would have expected some reaction… wouldn’t I?

I asked on some of the work-related Facebook groups. A chap with whim I went to college (all those years ago) posted a rather informative PowerPoint presentation from which I leaned loads. He also corrected my incorrect usage of the terms “homozygous” and “heterozygous”. I learned something.

But

Whilst these Facebook groups can be useful, you have to be selective in deciding to whom you will listen, and who you will ignore. Am I being arrogant in feeling that more and more they seem to be crawling with people who are planning to (yet again) re-sit GCSE science, and are looking sure to fail it again.

9 January 2020 (Thursday) - Antigen Incidence

Here’s something to make you think. This appeared on the Blood Bank Interest Group on Facebook posted by someone with whom I went to college (nearly forty years ago).

It is a scan of a blood group antibody panel that was being used in China in June 2005. Note also the need for Di(a) on the panel, that only three of the cells were D Negative, and that NONE of the cells were either K Positive or Fy(b+).

It is easy to overlook the racial variations of blood group incidences.

29 September 2019 (Sunday) - C antigens

Whilst perusing the Blood Bank Interest Group on Facebook I read “If a unit is negative for the C antigen will they also be negative for The C^W antigen”. Now this is easy. They might be. They might not.

But in the discussion that followed the question some said yes, some said no, and some agreed with me.

I need to bear in mind that I need to carefully consider my sources of CPD, and not blithely trust everything to be correct…