Hi All!

Do you still use 4C incubation when autocontrol does not come up at room temperature and you are having 2 cells out of 16 not pointing to any of the IgM antibodies? Resolving a back type discrepancy, a forward type looked like A but had extra reactivity with anti-A1 reverse cell = 3+. Short cold panel was run and plasma was negative with autocontrol only. So, we pulled a whole panel to identify the possible antibody reacting at RT. Anti-N was initially identified . So N negative unit was used to resolve the back type. But when review was being done, it appeared that 2 cells were 3+ positive but N negative and there were no extended typing found. We could not phenotype the patient for N bec she received transfusion 7 days ago. Since the autocontrol was negative with the same phase (RT), is it safe to result it as anti-N as the backtype was resolved with N neg segments and non specific cold at RT, for reevaluation when next workup will be performed? Or chances are, autocontrol may have come up at 4C if we did that and it might have been a cold auto?

3 minutes ago, WisKnow said:

Hi All!

Do you still use 4C incubation when autocontrol does not come up at room temperature and you are having 2 cells out of 16 not pointing to any of the IgM antibodies? Resolving a back type discrepancy, a forward type looked like A but had extra reactivity with anti-A1 reverse cell = 3+. Short cold panel was run and plasma was negative with autocontrol only. So, we pulled a whole panel to identify the possible antibody reacting at RT. Anti-N was initially identified . So N negative unit was used to resolve the back type. But when review was being done, it appeared that 2 cells were 3+ positive but N negative and there were no extended typing found. We could not phenotype the patient for N bec she received transfusion 7 days ago. Since the autocontrol was negative with the same phase (RT), is it safe to result it as anti-N as the backtype was resolved with N neg segments and non specific cold at RT, for reevaluation when next workup will be performed? Or chances are, autocontrol may have come up at 4C if we did that and it might have been a cold auto?

May I mention here that the antibody screen with provue was negative. Also, the A1 reverse cell was typed for N and it was positive.

Personally, I think that if the antibody does not react at 30^oC or above, you have been wasting your time, effort and reagents.  Even if it does turn out to be anti-N, anti-N is almost always clinically insignificant, unless the patient is S-, s-, when they will also be 'N' negative, or if they are homozygous for one of the HE genes, or are double heterozygous for two of the HE genes - all of which are very rare.  Would you really give N Negative blood in the situation you describe?

I am pretty sure we do not do a 4C incubation routinely for any reason.

Scott

48 minutes ago, SMILLER said:

I am pretty sure we do not do a 4C incubation routinely for any reason.

Scott

That's sort of what I meant Scott (although I think I could have put my own post better!).

Thanks Maicolm and Scott! The only reason why we had to identify the IgM antibody and differentiate it from Non specific cold and cold auto was to document how we resolved the backtype discrepancy. We're also worried of the clinically significant IgM behaving high incidence antibodies that may be on the way like anti-Vel and anti-Tja or PP1Pk if the autocontrol is negative or cold auto is not proven.