Ortho says it is OK as long as you perform you own validation, however, they are not willing to give any recommendations. We rarely do prewarm techniques, and our reference lab recommended prewarm for a patient with a strong cold autoantibody.  I would like to use gel instead of tube testing if possible.  Granted, it would be hard to come up with enough patients with cold autoantibodies for a validation study.  Any thoughts or experiences anyone would like to share?

This is one technique that I would not want to validate in gel.   Gel will enhance reactions and will pick up strong, direct agglutinins.  A microscopic reaction (negative) in tube could be a 1-2+ (positive) in gel.   I don't want to take the chance of enhancing unwanted reactions and would opt tube testing in this case.  I am interested if others have done this and their success or failure.  

I don't believe you can perform a strict prewarmed in gel due to the 10 minutes centrifugation cycle.  I always do prewarmed in tubes.

We attempted to validate a "prewarm gel" procedure, but did not have much luck.  As you say, it is not truly a prewarm method due to the 10 min centrifugation at room temp.  It seemed to work for patients with weaker colds, but if the cold ab was strong, the prewarm gel would usually still be positive.  We dropped it.

Agree with David and knelson. I played with prewarm gel and it just didn't work well, especially with stronger colds. I'd recommend sticking with tube.

I agree, pre warm, done correctly, should be done by a tube method. GEL will only enhance some colds. I think the pre warming of plasma and reagents with a warm wash phase will give the best results.