Cold agglutinin/DAT

[merky125]

We have a patient presenting with a CA, his titer is very high and he has a paraproteinemia issue also. He has never been transfused. Everything is positive or negative depending on what he is showing. By this I mean that he is A Pos but unless pre-warmed his back type is negative. His DAT is 3+ positive on a fresh specimen but his pre-warmed DAT is negative. Is it appropriate to report a pre-warmed DAT? We don't have a procedure for it but I can quickly write one if needed, as long as I know that it's kosher to do this.

Thanks

[Malcolm Needs ☆]

We have a patient presenting with a CA, his titer is very high and he has a paraproteinemia issue also. He has never been transfused. Everything is positive or negative depending on what he is showing. By this I mean that he is A Pos but unless pre-warmed his back type is negative. His DAT is 3+ positive on a fresh specimen but his pre-warmed DAT is negative. Is it appropriate to report a pre-warmed DAT? We don't have a procedure for it but I can quickly write one if needed, as long as I know that it's kosher to do this.

Thanks

I wouldn't worry about the high titre of the cold agglutinin, BUT I would be very concerned about the thermal amplitude of the antibody.

If I were you, I would incubate the patient's plasma at 30oC, and some test cells at 30oC, and then, once they have reached that temperature, mix them together and see if there is any reaction after leaving the tests at 30oC for about half an hour or so (direct agglutination).

Was the DAT positive by anti-IgG, anti-IgG and anti-C3d or anti-C3d only?

I would have no problems performing a DAT on warm-washed red cells; we do it all the time in cases of CHAD.

Sorry about so many questions!

:faq::faq:

[merky125]

Malcolm,

We have done a screen using pre-warmed plasma, cells, anti-IgG cards, anti-IgG reagent, C3D reagent, all nicely warmed first then mixed and warmed again. All turn out negative. Early AM today he got 2 units of blood with a blood warmer with no complications. Both the C3b/C3D and anti-IgG were positive at RT but negative pre-warmed.

I just wanted to hear that a pre-warmed DAT is OK to do.

Thank You