We have a patient that is O neg with a positive D control in gel and a positive screen due to a warm auto-antibody. 

Why is the D control affected by the warm auto, but the anti-A, anti-B and anti-D weren't?

Also how common is it to have a positive IgG DAT and positive complement DAT? The initial work up from our ref lab showed the warm auto and 4+ IgG DAT. Multiple days later, both the IgG and complement DAT were positive and the eluate showed an auto anti-e.

I don't know why the Control is positive, but the actual test is negative. In theory, the anti-D and control should be a matched set - they should be formulated exactly the same, except for the presence of the anti-D. Every manufacturer has "secret ingredients" - potentiators and other chemicals that stabilize and enhance the antibody reactivity. The controls, if supplied, should include the same ingredients.

If you are using a control from a different manufacturer or product line, it might explain your findings.

Are you saying that a monospecific anti-complement reagent is reactive with the patient's cells? It's not unheard of for warm-autos to bind complement, but since this looks like an autoanti-e, it would be highly unusual.

9 hours ago, exlimey said:

I don't know why the Control is positive, but the actual test is negative. In theory, the anti-D and control should be a matched set - they should be formulated exactly the same, except for the presence of the anti-D. Every manufacturer has "secret ingredients" - potentiators and other chemicals that stabilize and enhance the antibody reactivity. The controls, if supplied, should include the same ingredients.

If you are using a control from a different manufacturer or product line, it might explain your findings.

Are you saying that a monospecific anti-complement reagent is reactive with the patient's cells? It's not unheard of for warm-autos to bind complement, but since this looks like an autoanti-e, it would be highly unusual.

The forward type and D control are on the same gel card-so same manufacturer.

The DAT was tested at our reference lab as part of their warm auto work up. I believe the anti-complement reagent is monospecific, but I couldn't say for sure.