For the love of Pete!

[dotahill]

We are having such a hard time in our lab right now ruling out Anti-C and Anti-E with our 16 cell panel when the antibody is an anti-D. We are still doing tube testing. I was wondering if anyone has run into this and what you are doing to combat this. I am getting sick of sending samples to the ARC for an Anti-D. I am trying to figure out best practice, i.e. bringing in a 12 cell panel in addition to our 16 cell, or bringing in PEG. The panels are starting to be very unhelpful!

[Malcolm Needs ☆]

I don't know this panel whatsoever, but could you not enzyme-treat the r'r (if there is one)? This would rule it out, as Rh antibodies almost always react preferentially with enzyme-treated red cells. If it doesn't react with the r'r, there is little chance that there is an anti-C there as well.

If you don't have an r'r in the panel, I'm a bit stuck for an answer.

[John C. Staley]

Just a question or two, what is your criteria for ruling out? Who's panel are you using? I do recommend a 16 cell panel. We would run the first 12 and then if necessary the extra 4 would come in handy. Also it gave you 4 more cells to consider when looking for specific cells.

I remember panels where I could not rule out anti-Fya if the patient had an anti-E (Dade was infamous for that) but I don't remember having any problems ruling out either anti-C or E when an anti-D was present.

:juggle:

[David Saikin]

We can r/o Anti-C or anti-E with enzyme pretreated r'r or r"r . . . just like Malcolm says.

[clmergen]

Article from the 2008 IRL conference hosted by ARC (when they still did those). It has a suggested protocol for ruling out anti-C or anti-E in the presences of anti-D.

http://a1881.g.akamai.net/7/1881/26640/v0001/redcross.download.akamai.com/26640/pubs/immuno/24_2_08.pdf

[Mabel Adams]

We don't have enough use for it to keep enzyme. I allow rule out of anti-E & C in the presence of anti-D with a single heterozygous cell for each because the odds that I will give a unit that is pos for either is less than that I will give a Co b pos unit in an electronic xm to someone with an undetected anti-Co b. We don't worry much about that, do we? All but a couple of percent of D neg units will be C neg and E neg. Even if we missed one, we would be very unlikely to give more than one unit that is pos for either C or E to the same patient in the same testing episode. If the antibody is too weak to be detected with a hetero cell (especially with a sensitive technique like PEG or gel) it probably won't cause any noticeable transfusion reaction. Remember, we rule out anti-K with a single heterozygous cell on every negative antibody screen we do.

[John C. Staley]

Thanks Mable, I was waiting to see if someone else would cover this. Your explanation covered, exactly, the system we worked under which was why I was surprised some one was having trouble ruling out anti-C and anti-E when anti-D was present. That's why, in my initial response I inquired as the the rule out criteria being utilized.