Where I am working they do a tube group backup for any weak reverse reactions given by the analysers. In all previous laboratories I have worked in this has been done by setting up the group and then spinning tubes for 60 seconds at 1000rpm. Super quick and you get a lovely pellet that is easy to read. Where I currently work they do tubes but don't spin them, but incubate them on the bench for an hour then read macroscopically. If nothing is visible macrocscopically then you look microscopically and if still nothing is visible it is incubated at 4oC for an hour. This seems like a tremendous amount of faff when you can get a clear cut result so quickly.

 

I have asked 'why' and noone can tell me - just that they have always done it like that.

 

So my question is why are we doing a protracted and cumbersome method when a quick and cleasr method is available?

I would term this "institutional inertia".

Is this practice documented in a procedure manual? If so, what was the date of implementation?

Are you in a position to compile some data comparing immediate-spin tube test results with un-centrifuged tube test results?

I agree with Dansket, and in answer to your direct question, I would say YES!

I agree with Dansket, and in answer to your direct question, I would say YES!

 

I'm confused, it wasn't a yes/know question... Are you saying it is cumbersome and spun is preferable, or the other way round?

 

Monday is not my friend - my brain hasn't warmed up yet. I'm asking too many 'whys' lately

I'm saying that spinning is much better.

 

That having been said, you have to include a group O as a negative control, but I, for one, would go straight to 4^oC, rather than muck about with room temperature.

Malcolm,

If I'm incubating patient serum/plasma with test cells at 4C, I would also include an O cord cell (we have these in a hospital setting) as well as an auto-control.

Dan

Quite right Dansket, but in the UK, since the problems in Birmingham with the hospital keeping samples from foetuses/newborns without parental consent, we are now not allowed to use cord cells without direct consent, and so have to use adult ii red cells (and, of course, they grow on trees all over the place)!!!!!!!!!!!!

Well, in the very old days when I first worked in a lab,and before the days of monoclonals and gel, that was how we always did all our groups  (easily 100 per day) - 1 hour incubation on the bench then read macroscopically.  If you have a large number of samples, and special numbered racks this can have the advantage of not having to label every tube which, if you spin is a must.  One ABO/reverse group, without the D - anything from 5 to 8 tubes per sample to label with the sample number + the reagent.....OK for one sample but for lots of samples a huge source of error and VERY time-consuming. 

Malcolm - you're wrong about ii cells - they don't grow on trees - they grow on pads (i-pads- sorry  )

Well, in the very old days when I first worked in a lab,and before the days of monoclonals and gel, that was how we always did all our groups  (easily 100 per day) - 1 hour incubation on the bench then read macroscopically.  If you have a large number of samples, and special numbered racks this can have the advantage of not having to label every tube which, if you spin is a must.  One ABO/reverse group, without the D - anything from 5 to 8 tubes per sample to label with the sample number + the reagent.....OK for one sample but for lots of samples a huge source of error and VERY time-consuming. 

Malcolm - you're wrong about ii cells - they don't grow on trees - they grow on pads (i-pads- sorry  )

 

Unlabelled tubes makes me very, very uneasy. If I were to drop dead in the middle of a bench crossmatch I would want someone else to be able to take over without having to start over and delay the provision of the blood.

Quite right Dansket, but in the UK, since the problems in Birmingham with the hospital keeping samples from foetuses/newborns without parental consent, we are now not allowed to use cord cells without direct consent, and so have to use adult ii red cells (and, of course, they grow on trees all over the place)!!!!!!!!!!!!

Malcolm, I am on the other side of the pond. What happened in Birmingham?

Well, more or less as I said in my earlier post tricore.

 

Autopsies were carried out on foetuses and newborns (and children come to that) and organs were kept without the parents either being told or giving their consent (of course, they couldn't, as they were unaware that the organs were being kept), and so, when the bodies were released for burial/cremation, the parents were unaware that the bodies were not "whole".

 

This resulted in an Act of Parliament that has outlawed such a situation happening again (which has had all sorts of unwanted ramifications, such as the fact that we can no longer use cord blood in our tests [for ii, etc] without the parents consent).

It's caused problems it histology too as control sections used to be from 'known' cases but we can't do that either now. Instead the poor little furries have to die (rats). Unfortunately rat liver doesn't work in the same was as human liver so they are relying on 'donations'. I'm on the organ donor register but have specified not my liver - that can be used for control sections

If you are talking about weak backtyping from an analyzer like the Echo, why not just replicate routine testing for your backup method?  We just put 2 drops of plasma in an A1 cells tube and 2 drops in a B cell tube, spin and read at RT, just like we would do on a manual tube testing Group.  The Echo, in particular, can give weak backtyping reactions because it shakes hard and for a set time limit.  It can not respond as you do manually by backing off on shaking a patient if you notice a weak reaction.  That 1 hour method you mentioned is just asking for trouble with colds and rouleaux (if using plasma).  I would think a change in method could be encouraged. Good Luck

Our backup method for rapid group is to tile it. I want to introduce the spin method and showed why just yesterday. There was a weak D on the analysers and the stood out tube group looked negative. I spun the tubes for 1min at 1000rpm and hey presto an actual result that you don't need to investigate further.

 

I have asked for a tube head for the card centrifuge and the lab manager has tentetively agreed...

Auntie-D.  Please tell me you don't want to spin cards in a centrifuge other than a card centrifuge made especially for that card? 

Auntie-D.  Please tell me you don't want to spin cards in a centrifuge other than a card centrifuge made especially for that card? 

 

I'm talking about tubes.

Malcolm, If I'm incubating patient serum/plasma with test cells at 4C, I would also include an O cord cell (we have these in a hospital setting) as well as an auto-control. Dan

 

Why O cord cell? We use O cell and autocontrol at 4C.

I used to use them because they are I-, and, of course, auto-anti-I reacts optimally in the cold.  Now, we have to use adult ii.