Polyspecific

[linsie]

There were a few incidences with the use of polyspecific where the polyspecific is positive, but the IgG and C3b was negative. Is this due to technique or an underlying cold antibody?

[Malcolm Needs ☆]

It very much depends what is in your polyspecific. What antibodies are actually in this reagent?

Anti-IgG (given), anti-C3b (probably), but are any of these also present: anti-IgM, anti-Iga, anti-C3d, anti-C3dg?

[Mabel Adams]

Sometimes the different reagents are a little different in sensitivity. If the reaction was quite weak with the polyspecific, it might not show up with the anti-IgG if it was just a bit less sensitive.

[rravkin@aol.com]

I read somewhere where the Poly-Specific can potentially be some combination of IgG and IgM class antibodies. Might this make a difference in reactivity, anyone??

[Malcolm Needs ☆]

I read somewhere where the Poly-Specific can potentially be some combination of IgG and IgM class antibodies. Might this make a difference in reactivity, anyone??

It certainly can, which is why I posed the question about what was in the polyspecific reagent above.

[Dr. Pepper]

Interesting - I have seen this as well, weak reactivity with the poly AHG but negative with the anti-IgG and anti-C3b,C3d. According to my manufacturer (Immucor), it's the exact same clones in the monospecifics that are combined in the polyspecific, so one would think one or the other monospecific would react if the poly reacts. What may be different is how much the reagents are diluted, resulting in slight differences in sensitivity as suggested by Mabel.

[ANORRIS]

Who uses poly vs IgG AHG for tube T/S and XM?

[David Saikin]

I don't use poly at all.  Do DATs with the monos (use gel)

[David Saikin]

Who uses poly vs IgG AHG for tube T/S and XM?

 

Just an aside:  I remember when the big "switch" to EDTA specimens was happening.  The poly users were busting my chops 'cuz I used anti-IgG . . . they said I couldn't detect complement activation.  To the EDTA users I said "neither can you".  I haven't used polyAHG in over 20 yrs.  Most of the hospitals around me (gel and tube users) only carry IgG cards or anti-IgG, they send me their DATs for complement testing so I would guess that in Northern NH/Vt there are no polyAHG users (that I am aware of).

[AMcCord]

I don't use poly for T/S or crossmatch. I keep it in stock only for DATs - if negative we're done, if positive we do the differential. Routine cord blood DATs are done only with IgG.

[mollyredone]

Same as AMcCord.

[Dansket]

I dealt with this issue by doing DAT's on adults (upon physician request) with reporting separate results for anti-IgG and anti-C3d antisera so I didn't have to purchase the polyspecific reagent.

[aafrin]

We do the same as AMcCord and Mollyredone.