Rule out low incidence antibodies.

[Justina]

I was wondering if you guys suggest/practice ruling out low incidence antibodies? Ex. Your patient has an Anti-Fya and a panel cell reacted that is positive for the antigens Fya, V, and Jsa. Would you try to find and a panel cell negative for Fya and positive for Jsa/V to rule them out? Or would you just ignore it?

[Malcolm Needs ☆]

As a Reference Laboratory, we would try to find out the exact specificity in such a situation.

However, if it were a patient's plasma that had reacted with a single unit during cross-match procedure, we probably would not, as it would be like looking for a needle in a haystack, and even the best Reference Laboratories do not have access to red cells expressing all the different low incidence antigens or, just as importantly, access to serum/plasma samples that contain a single low incidence specificity. Remember that when an individual has made an antibody to, for example, anti-Wra, their plasma often contains antibodies to several other low incidence antigens (as a soup of antibodies), or the antibody cross-reacts with several low incidence antigens.

[jayinsat]

I was wondering if you guys suggest/practice ruling out low incidence antibodies? Ex. Your patient has an Anti-Fya and a panel cell reacted that is positive for the antigens Fya, V, and Jsa. Would you try to find and a panel cell negative for Fya and positive for Jsa/V to rule them out? Or would you just ignore it?

We would not try to find any additional cells in this case, UNLESS there was some unexplained reaction on the panel that did not fit the Fya pattern, (i.e., a Fya negative cell reacted positive and it was Jsa positive.), or the AHG crossmatch showed reactivity with a Fya negative unit.

We treat V, Cw, Jsa, Kpa and Lua this way.

Edited February 14, 2012 by jayinsat
wanted to add crossmatch incompatibility

[Justina]

Thanks Malcolm and Jay. We just have some people that rule out everything and some that do not, neither are wrong according to our policy/SOP.

[LCoronado]

We would not try to find any additional cells in this case, UNLESS there was some unexplained reaction on the panel that did not fit the Fya pattern, (i.e., a Fya negative cell reacted positive and it was Jsa positive.), or the AHG crossmatch showed reactivity with a Fya negative unit.

We treat V, Cw, Jsa, Kpa and Lua this way.

Same here.

[jill]

We do the same. If an alloantibody such as Anti-Fya happens to react with a panel cell that has a low incident antigen we do

not try and find another Fya- cell with that low incident antigen to rule out the possibility of that low incident specificity to be

present. Units will be crossmatched through the AHG phase.

[Rh-fan]

We only investigate the specificity of LFA antibodies when the reaction is very strong and we have enough cells of the donor for further investigation and during pregnacy only when the crossmatch between serum of the mother and cells of the father is possitive

[DOGLOVER]

If you have a low incidence antibody/ies do you just use crossmatch compatible red cells or do you request antigen negative? What if the antibody is historical only and not currently demonstrating so that you cannot trust the crossmatch? (the blood center does not have Jsa typing sera, patient has anti-Kpa, Cob,Jsa as well as E and S. 52 year old sickler who evidently did not get phenotype matched blood earlier in her life. Thanks for the input.

[Malcolm Needs ☆]

If you have a low incidence antibody/ies do you just use crossmatch compatible red cells or do you request antigen negative? What if the antibody is historical only and not currently demonstrating so that you cannot trust the crossmatch? (the blood center does not have Jsa typing sera, patient has anti-Kpa, Cob,Jsa as well as E and S. 52 year old sickler who evidently did not get phenotype matched blood earlier in her life. Thanks for the input.

We would only honour the anti-E and anti-S as far as this case is concerned, thus cross-matching E-, S- blood, and if these are compatible, give the blood.

[Rh-fan]

If you have a low incidence antibody/ies do you just use crossmatch compatible red cells or do you request antigen negative? What if the antibody is historical only and not currently demonstrating so that you cannot trust the crossmatch? (the blood center does not have Jsa typing sera, patient has anti-Kpa, Cob,Jsa as well as E and S. 52 year old sickler who evidently did not get phenotype matched blood earlier in her life. Thanks for the input.

We have had the same problem a few years ago and because of the lack of good typing sera and the absence of the antibody at that time we typed the donors on DNA.

Although not a LFA, we also do that for Doa and Dob antibodies.

Peter

[Malcolm Needs ☆]

Although not a LFA, we also do that for Doa and Dob antibodies.

Peter

Same here.

[Yanxia]

We have had the same problem a few years ago and because of the lack of good typing sera and the absence of the antibody at that time we typed the donors on DNA.

Although not a LFA, we also do that for Doa and Dob antibodies.

Peter

Peter，do you mean you do DNA typing for Doa and Dob or just do AHG crossmatch for those two antibodies?

Is it because antibody reagent to those two antigens is rare or there is other reason?

[Mabel Adams]

Remember your screening cells are almost always negative for Cw, Kpa, Jsa, Lua etc. You are not treating patients with antibodies badly if you don't require these to be ruled out. You are not ruling them out for any patients with neg Ab screens and in that case you aren't doing AHG xms probably like you are for patients with antibodies. If you use a 2 cell screen, you aren't even ruling out anti-f on your screen.

[Rh-fan]

Peter，do you mean you do DNA typing for Doa and Dob or just do AHG crossmatch for those two antibodies?

Is it because antibody reagent to those two antigens is rare or there is other reason?

I mean DNA typing and it is because of the lack of a good reagent

[Barbarakym]

We would not try to find any additional cells in this case, UNLESS there was some unexplained reaction on the panel that did not fit the Fya pattern, (i.e., a Fya negative cell reacted positive and it was Jsa positive.), or the AHG crossmatch showed reactivity with a Fya negative unit.

We treat V, Cw, Jsa, Kpa and Lua this way.

Exactly our process here in So Cal..... Kym

[EDibble]

Thanks Malcolm and Jay. We just have some people that rule out everything and some that do not, neither are wrong according to our policy/SOP.

That sounds like a lot of work! Like the others, we do not rule out LFA unless there is unexpected reactivity on the panel.

[Abdulhameed Al-Attas]

• Low-incidence antigens are not usually found on screen cell and antibody panels.

• Antibodies are hard to test for, but it is usually not difficult to find compatible blood.

Suspect this antibody if an AHG crossmatch is incompatible and other causes have been ruled out, such as a positive donor DAT or ABO incompatibility.

Examples of low-incidence antigens include: C^w, V, Kp^a, Js^a.

When going through the process of Ruling Out, antibodies like anti-V, anti-C^w, anti-Lu^a, anti-Kp^a, and anti-Js^a usually fall into the "unable to rule out" category.

[Auntie-D]

If they aren't going to cause a transfusion reaction, is there any point?

[Removed]

Removed

Edited June 3, 2015 by RollSlow10

[sschwartz]

Does anyone have any reference material to support the practice of not pursuing the rule out of LFA discussed here?  I haven't been able to find anything in my searches thus far.

[Malcolm Needs ☆]

I'm sure I have, but I am at home today.  I'll have a look when I get to work tomorrow.

[tbostock]

We would not try to find any additional cells in this case, UNLESS there was some unexplained reaction on the panel that did not fit the Fya pattern, (i.e., a Fya negative cell reacted positive and it was Jsa positive.), or the AHG crossmatch showed reactivity with a Fya negative unit.

We treat V, Cw, Jsa, Kpa and Lua this way.

Same here

[Malcolm Needs ☆]

Hi sschwartz,

 

The very best reference I can give on this is an Editorial by George Garratty (not a bad serologist!!!!!!!!!) entitled, "How concerned should we be about missing antibodies to low incidence antigens?" from Transfusion 2003; 43: 844-847.

 

Although this is, obviously, a bit old now, the situation has not changed in the intervening years, as far as I know.