Mixed fields

[dboutin]

I would like to know if some people are grading mixed field 1 +, 2+ or if you are using only the terme mixed fields

Thanks

[David Saikin]

I grade mf reactions when they are noticed.

[rrcc1974]

mf=POSITIVE with no grading

[Yanxia]

I grade it, too.

[dboutin]

I would like to know if some people are grading mixed field 1 +, 2+ or if you are using only the terme mixed fields

Thanks

Why are you grading MF since this happens is some particular situations.

[Mabel Adams]

I like to grade mixed field. It gives a better record of what the tech actually saw.

[Yanxia]

To grade the mix field we can differentiate A3/B3 to Aend/Bend subgroup, and when a type A patient been given type O cells ,if not too much,we can see the anti-A agglutinate lots of cells instead of a few of cells which will reflect through the grading report.

[geekay]

no grading...

only the word "mf" is used.

best wishes..

[David Saikin]

I need to amend my previous post - in gel we just use mf, but if tube testing, we grade the reaction with the mf superscript.

[Mer]

We just say MF. Regardless of grading, there are still transfused/passive cells in there - so we don't really see any difference.

[LaraT23]

We definitely grade mixed field, helps with gel for colds and rouleaux and also in tube. I actually used that just last week to help ID a lutheran A. It has a characteristic mixed field appearance in the tube and is only 1+ in gel.

[Rosemary]

As we do stem cell transplants here, we grade our mixed fields to get an indication of engratment for our ABO mis-matches. These groups are performed in tube.

[Melanie]

Grade reaction and notate "mf"

[L106]

Grade rxn and note "mf". (Same as Melanie.)

[NedB]

When you see a mixed field (cut and dry with gel) the importance is to figure out why. Dual populaions because of different group or Rh transfusion? If this is known and the reason is benign, the strength does not matter. If the reason is not benign (Rh+ to Rh-) you would want to follow the survival of the Rh+ cells - so record the strength. If you are tube testing and this is an antibody screen and are considering Anti-Sda, again the strength is part of the workup and needs to be recorded.

[rcurrie]

I was taught to grade mf reactions in SBB school (thanks, Clare), and found that grading is very useful with subgroup identification.

However, unless your bloodbank staff are all highly trained and mostly SBBs (like my former lab), you may be asking too much of the techs. I think most labs that have techs that rotate in and out of blood bank would be tickled pink just to get techs to recognize mf reactions at all.

BC

[Malcolm Needs ☆]

We grade mixed field reactions and then put "mf" as a superscript.

Grading can be useful. Say, for example, you are seeing a patient for the first time who is destined to become transfusion dependent. You perform a full (C, c, D, E, e) Rh type and a K type. They have already been transfused, are adult and have been given 2 units of red cells. If they are going to become transfusion dependent, you would want to transfuse them with blood that lacks the antigens that they themselves lack (or, at least, those antigens that are highly immunogenic). Say the patient is R1R1, K-, but gives a weak mixed-field reaction with anti-c and or anti-K, it is pertinent to give an "educated guess" (and I freely admit that it is a guess) that, as the patient has only been transfused with 2 units, they are, in reality, c- and K-, and we would then advise that, in future, they are transfused with c- (or even R1R1), K- blood, so that they do nor make anti-c and/or anti-K.

We would only make this "educated guess" when we know the transfusion history and that they are likely to become transfusion dependent.

Of course, these days it is easier. You can get the patient genotyped, if such a service is readily available to you.

[TeachBB]

we grade the strenght of agglutination and append "MF"

[PammyDQ]

This is a topic which is of great interest to me. First of all, when our BB LIS system was set up, there was no grading reaction "MF" created as a postive reaction, forcing us to enter a numerical result 1+-4+, then commenting that the reaction is mixed field. We use the MTS Gel system, so mixed field reactions are extremely obvious with ABO/Rh typing.

To complicate matters, we have a bone marrow/stem cell transplant unit that has been doing an increasing number of major and minor mismatched transplants. With recipients blood types changing with chimerism and with transfusion of type O blood which is then needed, we're seeing a heck of alot of mixed field. BUT NOW we're being asked to semi-quantitate the PERCENTAGE of O vs. A or B cells in the gel column!!

A project my medical director suggested is to set up samples of various percentages of red cell suspensions to use as a reference. I have yet to do this as we've been very busy and we're a "tiny" BB (only 2 techs day shift, 1 eves).

ANY SUGGESTIONS?? Any one else with a similar predicament??

[transfusionpgi]

we do grade mf and I agree with rcurrie that grades are extremely helpful in picking up weaker groups.

One more thing, has anybody noticed these mf reactions on "slide"? These appear 'beautiful' and you can actually see them getting stronger from "within-out" and differentiate them easily from weaker reactions say 1+ or 1+(w), especially for techs who are not very interested somehow in picking these reactions!

[Malcolm Needs ☆]

I agree with you transfusionpgi, but careful that you do not misinterpret an anti-Sda or an antibody within the Lutheran Blood Group System, which can also appear like this on slides.

[NedB]

PammyDQ

In the cross-type bone marrow transplants we've had, the MDs have been more concerned about the final conversion of the reverse type. The forward type converts failrly quickly, and we usually give type O and Rh specific until the reverse type reacts at AHG like the forward. At that point, the need for transfusions drop off to nil.

[Malcolm Needs ☆]

Hi NedB,

I've noticed that the reverse group can sometimes take an extremely long time to convert to that of the donor. It is in situations such as a group O donor being transplanted into a group A recipient, who is also a Secretor. In such cases, the anti-B shows through fairly quickly (as you would expect), but the anti-A does not.

The hypothesis is that the recipient will still be producing A substance (Type 1 backbone) and that the transplanted immune system either does not "see" the A antigen as foreign, as, when tested by sensitive techniques, it is possible to adsorb and elute anti-A from the apparent group O red cells, or that the A substance is "mopping up" the anti-A produced by the donor's transplanted immune system.

Have you experienced the same phenomenon at all?

[NedB]

Tthe Patients here who have taken the longest to convert have been from Type O Pos to A Neg and from O Pos to AB Pos. Both og these Patients are still doing well and have not needed further transfusions, so I really have no long-term follow-up Blood Bank results.