Unknown antibody

[Dr. Pepper]

Your lab receives a specimen on an outpatient who is scheduled for a transfusion the next day. The patient has no previous history and types O Positive. 2 of 3 antibody screening cells and 6 of 11 panel cells react weak + to 2+ in PEG/AHG. Auto control is negative. Immediate spin reactions were negative. There is no apparent pattern to the reactions. Nothing matches up to the stronger reactions (1+ and 2+). All antibody choices can be ruled out with homozygous cells, except anti-E and anti-N which can be ruled out with heterozygous cells. Anti-K cannot be ruled out, but only 4 of the 8 reacting cells are K+. Your tech says "It looks like it wants to be something, but I have no clue what this is!", punches out and leaves for vacation in Florida (true story). You don't have much sample left. You don't want to delay the transfusion or have to send a phlebotomist out to the patient's home to draw the patient again. How might you proceed?

[Yanxia]

If I have the anti-serum to K,E,N,I will test the patient for those antigen. Then chose the can't exclude antibodies neg cells to crossmatch use PEG/AHG method then to transfuse.

[Bill]

I would check the antigram to see if the 4 Anti-K cells that are not reacting are heterozygous for K; if so I would use K Neg packed cells that are AHG compatible. I would also screen for E but do not have N typing serum. If I cannot get K-E- packed cells AHG compatible, would have to postpone transfusion, redraw and send to reference lab.

[Dr. Pepper]

I would check the antigram to see if the 4 Anti-K cells that are not reacting are heterozygous for K; if so I would use K Neg packed cells that are AHG compatible. I would also screen for E but do not have N typing serum. If I cannot get K-E- packed cells AHG compatible, would have to postpone transfusion, redraw and send to reference lab.

Please excuse me if this wasn't clear: 8 of 14 reagent cells reacted with the serum. Of those 8, 4 were K+ (heterozygous) and 4 were K-. Therefore we could not eliminate anti-K. (And if anybody routinely has homozygous K+ reagent cells, lucky you!)

[JOANBALONE]

I would have no problem with giving E negative, AHG compatible red cells for transfusion. K is ruled out in my opinion. I would not worry about N.

JB

[Malcolm Needs ☆]

I would quite definitely send it to a Reference Laboratory.

You have no proof that it is a single specificity, as your panel cells will not cover all specificities (only the common antigens). If it does turn out to be an anti-N, then no problem, but if it does turn out to be a mixture, and one of those is clinically significant, it is better to delay the transfusion than to put the patient in danger (that, and the fact that I work in a Reference Laboratory, and we need all the work we can get - within reason!!!!!!!).

:D:D:D:D

[Dar]

Get more specimen! Try enzyme, another enhancement media, or a reference lab. Too many positives to ignore, and not enough positives to be "crap":)

[Eagle Eye]

Patient has no previous history at your hospital? can you get TX history from the patient?

I would not transfuse until I complete the workup. DO enzyme, complete phenotyping and if still not conclusive, send it to ref. lab.

In emregent case I would atleast give K-, E- crossmatch compatible or even try to give phenotypically matched crossmatch comaptible unit.

[Dr. Pepper]

There were some sound suggestions for transfusing in light of only what I had presented, and some suggestions for further workup. Of course, like any blood banker, I wanted an explanation for the reactions. Here's what we did:

I tested 6 cells from a different panel lot. I noticed a few looked grainy at immediate spin. After 15 minutes at room temp 5 of the cells were 2+. They were all P1 positive. The one cell not reacting was P1 negative. I tested the remaining 2 P1-neg cells. All three P1-neg cells were negative at IS, room temp and PEG/AHG. The patient was P1-neg and I was satisfied with the antibody ID. There was no sample left, but we asked Oncology to draw the patient when he came in the next day and we were cautiously optimistic that he wouldn't have to wait too long for his blood. We decided in the interest of time to just find 2 P2 units to be ready to crossmatch to him. We got more sample the next morning. His crossmatches were fine. We eliminated anti-K as a possibility with a K(+) P1(-) cell and treated the serum with P1 substance. The treated serum did not react (in PEG/AHG) with most of the P1(+) cells that reacted the day before, including a E(+) homozygous cell. So we got to eliminate anti-E with a homozgous cell. We weren't concerned with anti-N, but that could be eliminated as well with the treated serum. He got his blood uneventfully about an hour after we received his new specimen. And my students got a nice sample for paneling, prewarming, P1 neutralization and other serological fun.

I probably would not have bothered to present this case but I had just read Brenda's excellent advice on another thread "Incompatible CM" (and I was happy to get an answer to the problem and not have to transfuse the patient with our fingers crossed or send it across the Atlantic to Malcolm's lab!). We are all taught that you if eliminate antibody choices with heterozgous cells, you do so at your own peril, as antigen-positive cells may not react due to dosage or other variations in antigen strength such as we see with P1. Like Brenda, I also try to teach my techs and students to look in the other direction when a problem doesn't add up: what do the cells that do react have in common? (I was thinking anti-P1 or other cold auto/alloantibody.) Then you can try to do something to get those remaining antigen-positive slackers to react for you. And it was a good reminder that IgM and IgG may pop up in places where you might not expect them.

Edited December 14, 2010 by Dr. Pepper
spelllling

[Malcolm Needs ☆]

Excellent case Phil.

Anti-P1 is the oft forgotten antiboy.

Edited December 14, 2010 by Malcolm Needs

[Yanxia]

Pepper, thanks to share this case with us.

But in my memory most of anti-P1 is IgM, so you would get positive immediate spin, but the post before you said it is neg. Am I misunderstand it, because my English?

[Dr. Pepper]

IgM does not always react "immediately" - sometimes you can get better reactivity after a few minutes incubation at room temperature. You can see this easily doing ABO typings: if your serum gives weak reactions with A1 or B cells, just spinning it down a second time (a 30 second incubation maybe?) will often give you a significantly stronger reaction. So the first worker did not see anything with her antibody screen and panel at immediate spin and did not do a room temperature incubation. When I tested it again, I thought I saw some very weak reactions and I did do a 15 minute room temperature incubation and found the anti-P1. (I was also looking for an IgM antibody anyway.) Why did I see it and the other worker not see it? It could be technique, or how cold the reagent cells were that were tested, or if there was a slight delay between setting up the tests and reading. Again, the immediate spin reactions I saw were not strong.

And Yanxia, your English is fine. I have always been impressed by your obvious hard work and interest in these discussions, and you are a very valuable contributer to the forum. I certainly could not do it in Mandarin or any other language for that matter!

[L106]

Nice case study, Dr. Pepper. And very true-to-life....I've seen similar cases where (as your tech described) "it looks like it really is trying to be something, and it's too much to ignore, but it just isn't matching anything" and many times the culprit turns out to be Anti-P1 (where antigen strength can vary significantly from individual to individual) and Anti-M (reacting only with homozygous cells.)

(Sometimes those darn antibodies forget to read the rule book!!)

Donna

[Liz]

Thank you Dr Pepper, very informative.

[rravkin@aol.com]

Phil,

How come P1 was not recognized or considered in your initial testing? P1 typing is usually given in the panel histogram.

[Yanxia]

Phil,

How come P1 was not recognized or considered in your initial testing? P1 typing is usually given in the panel histogram.

I have the same doubt. At first I think this maybe the differ between race, becase in ascia we us the different panel histogram at least differ in some antigens.:p:pSo I have not ask it.

[Dr. Pepper]

Our reagent cells do have P1 types listed. I think the tech who did the initial testing didn't consider anti-P1 because there were no reactions at immediate spin, there were reactions (some quite strong) in AHG which made it look like it was an IgG antibody, and 3 of the P1-positive cells did not react at all.

[Liz]

Very good point Phil and draws ones attention to rethink an antibody. Thank you!!

[PammyDQ]

Gee Phil, sounds like a same patient I did here at RWMC a few weeks ago...but our guy is AB+. I guess there's 2 of them walking around the area right now!

[AMcCord]

The 'so-called' cold reactive antibodies were put on earth to keep Blood Bankers humble. Just when you think they can never fake you out again, one arrives on the scene and does just that. I get a lot of panels that evening and nite shifts can't figure out that turn out to be one of those devious little 'cold reacting' devils pretending to be something with IgG specificity or a warm auto that pretends to be an alloantibody.

[Malcolm Needs ☆]

The 'so-called' cold reactive antibodies were put on earth to keep Blood Bankers humble. Just when you think they can never fake you out again, one arrives on the scene and does just that. I get a lot of panels that evening and nite shifts can't figure out that turn out to be one of those devious little 'cold reacting' devils pretending to be something with IgG specificity or a warm auto that pretends to be an alloantibody.

Yep, when I was working in the hospital environment, I sent an anti-P1 to the Refrence Labratory for identification. Embarrassed or what!!!!!!!!!!

:redface::redface:

[Brenda K Hutson]

Looking at your positive reacting cells, is there anything that they "all have in common?" Forget what you have ruled out for a second; what things to they have in common? May have to separate it out a little based on strength of reactivity (i.e. what do all of the 2+ cells have in common; etc.).

Brenda Hutson, CLS (ASCP)SBB

Your lab receives a specimen on an outpatient who is scheduled for a transfusion the next day. The patient has no previous history and types O Positive. 2 of 3 antibody screening cells and 6 of 11 panel cells react weak + to 2+ in PEG/AHG. Auto control is negative. Immediate spin reactions were negative. There is no apparent pattern to the reactions. Nothing matches up to the stronger reactions (1+ and 2+). All antibody choices can be ruled out with homozygous cells, except anti-E and anti-N which can be ruled out with heterozygous cells. Anti-K cannot be ruled out, but only 4 of the 8 reacting cells are K+. Your tech says "It looks like it wants to be something, but I have no clue what this is!", punches out and leaves for vacation in Florida (true story). You don't have much sample left. You don't want to delay the transfusion or have to send a phlebotomist out to the patient's home to draw the patient again. How might you proceed?

[jcdayaz]

Yep, when I was working in the hospital environment, I sent an anti-P1 to the Refrence Labratory for identification. Embarrassed or what!!!!!!!!!!

:redface::redface:

HAHA! Yes, very embarrassing:redface: Sounds like the time early on in my career that I sent what turned out to be an Anti-M to a reference lab.:redface: