We all 'rule out' many antibodies every day with 1 homozygous cell on our Antibody Screens ... and we perform immediate spin crossmatches based on that result ... and nobody flinches.

The 3 cell rule is for antibody identification ... you need 3 to be statistically sound. In other words, don't call it an Anti-K unless you can show me 3 K-pos cells that reacted without any other possibilities. And I'll need 3 Jsb-negative cells if you want to call it an Anti-Jsb. And so on ...

Gel or not ... heterozygous cells don't count much. We've got a few examples of antibodies that react ONLY with homozygous cells even in gel.

In selected cases (as with the M posted above) you gotta do what you think is right. If the reaction strengths make you worry that there is something more there, then find the cell that will make you satisfied you really ruled it out. Or antigen type the patient. That's different than a procedural rule or even a rule of thumb.

We use 1 Homozgyous to rule out. No heterozgous rule outs except by supervisor approval. Of course most antibodies have more than this. Multiple antibodies is where we use only 1 most of all.

With that said, we rule in with 3 examples, hetero or homoz. And yes you have to use your brain, look at what is in front of you. I have called an antibody where 1 homozygous was there to rule out but only explanation was that antibody.

I agree with Ms Croke!!

The 3 cell rule is for antibody identification ... you need 3 to be statistically sound. In other words, don't call it an Anti-K unless you can show me 3 K-pos cells that reacted without any other possibilities. And I'll need 3 Jsb-negative cells if you want to call it an Anti-Jsb. And so on ...

Gel or not ... heterozygous cells don't count much. We've got a few examples of antibodies that react ONLY with homozygous cells even in gel.

So true. Don't allow heterozygous except in rare situations (Anti D, for C and E, very few others). For initial identification we require 3 to rule in. and 3 to rule out as stated. But for confirmation, 1 will do. And I do like to confirm. It is how I found a patient was going regularly to another state and getting transfused when they came back and had an old antibody that was no longer showing at 3+. We called the other hospital. Got us all to the same place (she had 4 clinically significant antibodies) and talked to the patient about how important it was for her to tell any new providers about her antibody history.

Kym

Since we're on the subject off exclusions and confirming specificity, I have to post yet another pet peeve. These are 2 different processes. The first is exclusion by 1 double dose cell (or # of single dose ). Then looking to see if you have 2+/2-, or as we do in a ref lab 3+/3- to assign specificity. The result of the first step is a list of possibilities that must be confirmed by further consideration and possibly, testing.

When you have something as simple as -E or -K, you know you will have the required number of +/- using one panel. But both steps should be performed while keeping an open mind about the possible outcome no matter how simple the case. I had a staff member mistake an anti-Jkb for an anti-E & -K because the E+/K+ cells were the Jk(a-b+) cells. Unfortunate coincidence but due to a preconceived idea of what was most likely and failing to investigate the possible -Jkb further, the patient received 4 units of which 3 were Jk(b+).

I know we all have war stories but we should be very clear how we teach antibody identification.

Since we're on the subject off exclusions and confirming specificity, I have to post yet another pet peeve. These are 2 different processes. The first is exclusion by 1 double dose cell (or # of single dose ). Then looking to see if you have 2+/2-, or as we do in a ref lab 3+/3- to assign specificity. The result of the first step is a list of possibilities that must be confirmed by further consideration and possibly, testing.

When you have something as simple as -E or -K, you know you will have the required number of +/- using one panel. But both steps should be performed while keeping an open mind about the possible outcome no matter how simple the case. I had a staff member mistake an anti-Jkb for an anti-E & -K because the E+/K+ cells were the Jk(a-b+) cells. Unfortunate coincidence but due to a preconceived idea of what was most likely and failing to investigate the possible -Jkb further, the patient received 4 units of which 3 were Jk(b+).

I know we all have war stories but we should be very clear how we teach antibody identification.

Here here!

In a time where fewer and fewer techs seem to be remaining in the field for more than a few years, it can make a big difference to patients to respond to a tech force that is getting younger by strengthening training programs including case studies, taking steps to motivate new employees positively, and beefing up continuing education. Even if you don't have case studies developed, you can hand a trainee a stack of your work-ups from the past month or so.

A team is only as strong as its weakest link and the patient is ultimately better off if everyone in the laboratory feels responsible for the professional development and training of its current "weak" links.

Here here!

I currently use a Rhig panel/D panel when I have reason to suspect a passive or allo anti-D. We currently use selected cells to r/o all common clinically significant antibodies with 1 homo cell. The exception is the C,E, and K antigens, for which we use 2 hetero. I've heard arguments about getting the same reactivity whether you use 1 or 5 hetero and that it technically doesn't matter. 

Does anyone here also have a D panel? and does it rule out the antigens mentioned above with 1 hetero or 2 hetero?

 

Thank you

Our policy allows for rule out with two heterozygous cells, but I've never been comfortable with that.  I've seen antibodies that were negative with many, many heterozygous cells, but when you test them against a homozygous cell they react.

We will rule out C and E in the presence of anti-D with a single C+c+ or E+e+ cell.  K may be also ruled out with a single K+k+ cell.

Can I add this:

1. As far as I know the Dutch guidelines state the single dose is OKMfor exclusion of anti-K ( 2 cells)

2. The same Dutch guidelines: in the presence of anti-D (only then) single dose OK for anti-C and/or anti-E

3. FRench guidelines require 3 cells, although they admit it is not something they can hold on to in "complex" mixtures 

4. I agree with Malcolm about the strange attitude of equaling 1 double dose to 3 single dose? As of immunohematology were mathematical ?

Well, after three pages, I only have  eric1980  on our side..

 

I don't know, but as per my short experience, It kinda suffices the need. Although, if ever you are unlucky, if you happen to come across an antibody to a more frequent antigen, let's say cellano, then problem it is.

PS. - We too keep panels 3 months expired. For exclusion purposes.

 

One homozygous is the best, but not always possible for antigens like K.

We use one homozygous or three heterozygous to rule out

In my experience if the patient has anti-K, I will see reactivity in all hetero cells tested.  If you experience variable reactivity (some hetero reacting and some not) then I would say you have support for testing multiple cells.

How many of you that test multiple hetero K cells to rule out anti-K have found anti-K with variable reactivity?

I have seen such an anti-K quite a few times over my 43 years in transfusion, mostly in reference laboratories.  I have also seen a few that only react with red cells showing presumed homozygous expression.

It seems to me like one would have to have very weak reactions to get any kind of variable reaction with something like K.  (And good luck finding a homozygous cell from a panel in your average hospital lab!)

 

Scott

On ‎7‎/‎28‎/‎2009 at 6:33 PM, shelleyk482 said:

One homozygous or 3 heterozygous.

So, what about all the antibodies that react ONLY with homozygous cells?  Very scary that you are ruling out with heterozygous cells ...

1 hour ago, JPCroke said:

So, what about all the antibodies that react ONLY with homozygous cells?  Very scary that you are ruling out with heterozygous cells ...

To a certain amount I would agree with you that it is scary, but I also have grave doubts that such a weak antibody would be clinically significant - and, if K+ blood is transfused, the anti-K would be a lot easier to detect next time around!

 

OK, so now I am wondering... is there an antigen-antibody complex that is only detectable in all cases with just homogenous cells?

Scott

Ideally it is great to rule-out with at least one homozygous expression, but it is not always practical. The anti-K scenario is a prime example as discussed, but for those of you who insist on a homozygous cross-out: Do you really delay an identification of an anti-D and a potential transfusion, just to rule-out anti-E and anti-C?

Most hospitals do not have access to r'r' or r"r" cells, so would you insist that the sample be sent to a reference laboratory for resolution?

Ruling-out with heterozygous examples is an acceptable practice when the situation warrants it.  Obviously, one should look at the "big picture" and if you are seeing reactivity consistently with only a homozygous expression of a certain antigen, then you wouldn't want to ignore that and rule-out on only a heterozygous expression (or 3 for that matter).

My advice though: When doing a heterozygous cross-out make sure you are using a technique that is considered an enhancement for the antibody in question and if in doubt, either call your local reference laboratory for advice or ship it to them for resolution.

4 hours ago, SMILLER said:

OK, so now I am wondering... is there an antigen-antibody complex that is only detectable in all cases with just homogenous cells?

Scott

Not that I'm aware of, Scott.  The words "only" and "all" would tend to make me say No.  

10 hours ago, SMILLER said:

It seems to me like one would have to have very weak reactions to get any kind of variable reaction with something like K.  (And good luck finding a homozygous cell from a panel in your average hospital lab!)

 

Scott

For those who use Ortho panels, the 22nd cell on the 0.8% B panel is always homozygous for K.

Has anyone every been cited by using 2 hetero rule out for rare (or with anti-D not too rare:) situations (ie-anti-D presence and trying to rule out E or C)? How about citations with keeping expired panels (as some in this string do)? I know for awhile some insepctors liked to cite on expired panels (typically inspectors that don't understand the qualitative world we live in:)! Would love to get a global US perspective on this (not intended to incite our luckier ExUS collegues:)