At the hospital I work, homozygous cells are preferred for rule outs but if we can't find a homozygous cell, we generally use three for all heterozygous cells or so I thought.  Yesterday, a co-worker tells me that we don't use 3 heterozygous cells because Kell doesn't show dosage.  I am concerned because I looked it up in a textbook and Kell occasionally shows dosage.  My question is not a who is right, who is wrong situation, but what I would like to know what is your procedure at your hospital?  I also want to be certain because I want to be safe.  Yes, I am fairly new to the field - 6 months experience.  Thanks! 

I learned that Kell does not display dosage.  My experience is that this is not true.  I also learned that I could r/o Kell system ags with a heterozygous cell.  If that is my only recourse, I have no problem doing so but I have plenty of cells to look for a KK or multiple Kk cells.

I am going to be REALLY unpopular here, but I'm going to say it anyway (because I am a pedant)!!!!!!!!!!!

 

Antigens CANNOT be either heterozygous or homozygous; only genes can be heterozygous or homozygous.

 

An antigen can be described as either showing homozygous expression, or heterozygous expression.

 

That having been said, is a red cell sample that types as K+k- phenotypically, genotypically K/K or K/K^o, or even K/k, with a mutation within the Kell gene that prevents the k antigen being expressed and detected with all anti-k grouping reagents (just in case anyone doesn't believe me - we had one!).

 

That's got that off my chest.

 

Now then, there is NO doubt that there are some anti-K's around that only react with K+k- red cells (dosage), but they are fairly rare, however, how many people use antibody screening red cells that are K+k-?  I doubt if there are any.  Therefore, we are all ruling out anti-K using red cells with apparent K antigen heterozygous expression on every single sample that (apparently) has no atypical alloantibodies present.  Am I wrong about this?

 

It follows, therefore, that, over the years, there MUST have been occasions when a patient with a very weak anti-K (one that is only detected using red cells that are apparently showing homozygous expression) and who has been transfused with K+ blood (do the maths).  As far as I know, there are no papers within the literature that report a case of either a delayed or an acute transfusion reaction as a result of this.  Yes, this may cause the anti-K to become stronger (and, hence, be detectable using an apparent heterozygous red cell sample showing K+k+ expression), but then, if this happens, you give K- blood.

 

So, my considered answer is that you can exclude using K+k+ red cells.

 

I shall now go and lie down!!!!!!!!!!!!!

As far as I know, there are no papers within the literature that report a case of either a delayed or an acute transfusion reaction as a result of this.

 

I often wonder about the prevalence of transfusion reactions that occur but are never investigated/identified serologically due to circumstances.

We don't worry about dosage with K.

 

Scott

godchild, as long as the patient doesn't feel ill, it is not a delayed haemolytic transfusion reaction (whether we investigate it or not).  It is, at worst, a delayed serological transfusion reaction.

We have the same protocol:  Preferably rule out with homozygous cells, if those cells are not available with our current lot/s, three heterozygous cells are acceptable. We normally have 3 lots of indated panel cells to use. We may use outdated panel cells as part of a panel of "select" cells if indated cells of the desired phenotype are not available.

 

So, my considered answer is that you can exclude using K+k+ red cells.

 

I shall now go and lie down!!!!!!!!!!!!!

Malcolm - I am glad you got that diatribe off your chest.  However, I am probably always going to refer to the expression of ags on red cells as either hetero- or homozygous, for 2 reasons (both of which are really invalid):  1: that is the way I learned them and 2: it is easier than adding"expression" each and every time I use the hetero/homo words. 

 

I do understand and appreciate your drive to provide us "iggerant" ones with the proper terminologies, usages, and whatever else your vast knowledge of the field deems prudent to divulge.  PLEASE DON'T EVER STOP!

 

ds

godchild, as long as the patient doesn't feel ill, it is not a delayed haemolytic transfusion reaction (whether we investigate it or not).  It is, at worst, a delayed serological transfusion reaction.

 

I didn't intend to come off as questioning your post. That topic is just something that I have often wondered about after my experience in a hospital transfusion setting, where it seems like some possible reactions are definitely under-reported while at the same time we get workups on patients that weren't warranted.

We recently had a patient who was in the process of making an anti Kell (at least that is what it appeared to be). We happened to have a KK cell on the panel when we first tested the patient, and the reaction was 3+ with that cell, and + with all the other K positive cells (hetero of course). Several weeks later, the patient returned and now all reactions were the same strength. This is the only time we have ever seen this here. Stuff happens!

 

As a previous BB director here used to say, "There are no guarentees in Blood Banking"

 

   

I'm going to continue to be pedantic, even if it means I am banned from this site!!!!!!!!!!!!!!!!!!!
 
By producing an anti-Kell, Elizabeth, do you mean that the patient was producing an anti-K, or do you mean that the patient was a Ko, and was beginning to produce an anti-Ku???????????????????????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

And why does ruling out with 3 single-dose cells improve your odds over using 2 or even 1?  It doesn't make the antigen on one cell stronger because you ran two others. I know there is a chance that 1 cell has a weaker antigen so running 2 means that you have a better chance that at least one cell will pick it up.  I still think the places that require 3 rule out cells have the rule of 3 for identifying an antibody mixed up with what it takes to rule out.  Have I ranted on this before maybe?  

Yes Mabel your reply certainly makes sense! It also takes a lot of time to try and find 3 cells to rule out, especially with antibodies to high incidence antigens..... Rant away!

Malcolm, I believe there is a section header in Issitt & Anstee's book that says "There is no anti-Kell."  The first time I saw that (before I read the paragraph below), I almost fell off my chair.  Issitt could not write a text book without putting those little things in there either!

To take this one step further, with regards to Mabel's post, I am curious if the folks that allow 3 cells with heterozygous expression  to rule out, do you use this logic for all antibodies or just to rule out anti-K. I was never taught that it was OK to rule out using cells with heterozygous expression if you could find a cell of homozygous expression. Anti-K is frequently an example of this as is anti-E in the presence of anti-D and anti-C. The previous blood bank supervisor in our blood bank allowed rule outs using 3 cells of heterozygous expression but I prefer not to, except in the aforementioned cases.

Mabel, I agree completely. I've always been curious as to the logic of using 3 cells of heterozygous expression for exactly the reasons you mention.

We also happily use just one K+k+ cell on our antibody screens, as well as often S+ and other antigens of heterozygous expression.

I think the "There is no such thing as anti-Kell" was in earlier editions as well. I was wondering how long the thread would go on before that raised Malcolm's dander, too. Please keep it up Malcolm. I now always say anti-K, but I don't think anyone else in the lab does! At least they know what I'm talking about. I think.

Try using anti-K1 and anti-K2!  I always tell the students that is what they should be called - but don't expect me to be able to remember it.  Anti-Big K and anti-little k frequently make more sense to students because of the similarity to the Rh antigens terminology.

Try using anti-K1 and anti-K2!  I always tell the students that is what they should be called - but don't expect me to be able to remember it.  Anti-Big K and anti-little k frequently make more sense to students because of the similarity to the Rh antigens terminology.

Not to nit pick but the ISBT terminology is KEL1 and KEL2 - I still like your post.

You are going to HATE me David, but those are the genes - and should be in italics!!!!!!!!!!!

Yes and in playing the game of semantics, anti-K1 and anti-K2 are both incorrect terminology.

I think K2 is a mountain.  

I love this thread - the blood bank geek in me is enjoying this very much!!!

Mabel got me thinking (always a dangerous exercise), is there a K1, K3 etc mountain? And who was the mysterious "K" they're named after? Other inquiring minds may paste this into their browser and find out:

http://www.gearthhacks.com/dlfile29751/K1,-K2,-K3,-K4,-K5-mountains.htm

Of interest is that most sources credit the name of the system (blood group that is) to a Mrs. Kellacher, who had a baby with HDN, but several others spell her name as "Kelleher".

Phil

Other things are that "Cellano" was actually "Nocella", "Lutheran" was actually "Lutteran", the first antibody/antigen discovered in the Kell Blood Group System was anti-Kpc/Kp©, so the system should be called Levay, and the first antibody/antigen discovered in the Diego Blood Group System was anti-Wra/Wr(a), so that system should be called Wright!!!!!!!!!!!!!!!!!!!!!!!!

You are going to HATE me David, but those are the genes - and should be in italics!!!!!!!!!!!

I am sure they are the genes but in the USA they are also the ISBT terminology for the antigenic expressions.  I try to use them when I report out abs to other institutions.  Even the AABB Technical Manual describes these ags as K (KEL1) and k (KEL2).  Could be we are not as astute on this side of the pond.

 

I don't HATE anyone - it is not worth my energy to do so.

 

You are a GREAT RESOURCE so never hesitate to correct me.