Gel Phenotype testing for Kell

[LindaO]

We have been thinking of performing Kell phenoptyping in Gel. Our reagent is Ortho's Kell antisera for indirect antiglobulin testing. Has anyone tried this?

[David Saikin]

I use the Immucor Monoclonal anti-K with the buffered gel. Works great!

[Malcolm Needs ☆]

We do almost all of our K, k, Kp(a) and Kp( typing by gel, however, it's not great for detecting some McLeod phenotypes, as they react more strongly than you would expect.

To detect that they are actually McLeods, and not normal Kell types, you sometimes have to perform a titration.

[David Saikin]

What do you mean by stronger than you would expect? Would I not expect them to be very weak . . . and in the hospital setting, I may not be aware of dx that includes McLeod's. This is what happens (esp on this website) when you get reference experience vs the clinical BB. I love it . . . thanks Malcolm. But - please explain further.

Do you think the stronger rxs are gel related? I noticed with the ALBA D panel that I could get reactions with all antisera vs pos and neg rxs using tubes (with patient cells).

Edited September 11, 2011 by David Saikin
had a thought

[Malcolm Needs ☆]

Hi David.

No, it's not so much a function of the gel test, it is more a function of the modern monoclonal antibodies.

We have all "grown up" learning from text books that the McLeod phenotype gives you very weak reactions with, usually, anti-k, anti-Kpb and anti-Jsb, but, as with most things human, this is not entirely true. Sometimes these reactions are very much weaker than the controls, but sometimes they are only a little weaker.

With modern monoclonal antibodies, the reactions with anti-k, anti-Kpb and anti-Jsb can be as strong as the controls, seemingly ruling out a McLeod phenotype, but, actually, if you titrate these antibodies and use the control cells as one set of red cells and the "McLeod" cells as another set of red cells, there is a noticable difference between the end points of the two.

So, what I am saying is that, with modern monoclonal antibodies being so strong, a McLeod phenotype may be dismissed, because the initial reactions are "too strong", but, actually, they are McLeod phenotype, albeit at the stronger end of the continuum.

[Generic]

We use the Ortho anti-Kell on our Provue and it works great

[Eagle Eye]

We use Ortho anti-K with IgG gel cards and it works great. We make 0.8% suspension of donor cells using MTS 2. We take 50microliter of 0.8% donor cell and 25 microliter of anti-K in IgG gel card, incuabte for 15 mins and spin...works great.

[Eagle Eye]

We use the Ortho anti-Kell on our Provue and it works great

How do you program it? RUn it as a crossmatch???

[Hooper]

Did you do validation studies between tube and gel for the Kell phenotyping? How many samples? Thank you.

[Generic]

How do you program it? RUn it as a crossmatch???

Yep, we run it as an AHG crossmatch. We'll stick on the K+ and K= controls followed by the samples we want to test and just run them as a batch anytime we want to K a group of samples, as it generally isn't more than once every few days.

We validate every test we perform on the Provue...I don't know how many samples they used during the validation though, it was done before I started at this job.

Edited September 12, 2011 by Generic

[Townsend]

We do the same as aakupaku. We ran about 20 patients and 20 donors in duplicate (or compared to reference lab reports) for validation testing. We would not use our typing results as a workup for McLeod - that would go to our experts at the IRL.

Stephanie Towsend, MT(ASCP)SBB

[Eagle Eye]

we used 20 donors. One of them gave discrepancy due to positive DAT on donor by gel. Gave false postive result with kell typing. DAT by tube on same donor was negative. Just to be safe we added 20 more donors and all of them matched with tube testing. We do not use Gel for patient typing.

[galvania]

Malcolm, where are you getting monoclonal anti-k, Kpa and Jsb please?

[Malcolm Needs ☆]

Malcolm, where are you getting monoclonal anti-k, Kpa and Jsb please?

Hi Anna,

I'm afraid that you have caught me on a day when I am away from my office.

I'll let you know tomorrow, but I do know that the anti-Jsb we get from the New York Blood Center.

Malcolm

[Malcolm Needs ☆]

Right then, the anti-K is in the DiaMed/Bio-Rad gel cards, and they state that it is monoclonal (but I have no idea of the clone).

We also have an anti-K-like we use for screening for rare donors that we get from the IBGRL.

The anti-k we get from Sanquin.

Our anti-Kpa is polyclonal.

The anti-Kpb is actually an anti-Kpbc that we get from the IBGRL. Again, we use this for screening for rare donors, but we do play with patient's cells with it when the occasion arises, otherwise we use a polyclonal anti-Kpb.

As I say, our anti-Jsb we get from the NYBC. Once again, we use this for screening for rare donors, but we do play with patient's cells with it when the occasion arises, otherwise we use a polyclonal anti-Jsb.

We are sadly bereft of routine anti-Jsa at the moment, but that, if my memory serves me correctly, is polyclonal. We do have some human anti-Jsa from SCARF in an emergency.

Our other, rarer Kell-related antisera, such as our anti-K11 and our anti-K17, are human (from the propositi in these cases), and these are either from our own patients or from SCARF.

Hope that helps Anna.

[Eagle Eye]

what do you use for your controls as ProVue requires whole blood/packed cells...