2+ anti-D reactions in gel

[johna]

Invariably we are finding that reactions with anti-D in gel as high as 2+ turn out to be <1+ in the first tube when a saline tube titer is performed. Is anyone else experiencing this? If so, would you consider it a waste of time to titer 2+ anti-D gel reactions?

[bbbirder]

I would run in tube straight before I did a titer. Ususally these are very weak or not even detectable in tube.

Linda Frederick

[Mabel Adams]

I would turn these out as "too weak to titrate" if tube testing of neat sample was < 1+ in tube/saline/IgG. One could also say "Titer < 1" which is what I did if I had gone ahead and done the titer and it came out neg (or <1+) in the first tube.

[NedB]

Or you could just do the titer in gel. Pipet 50 mcL R1R1 cells onto gel cards and add 25 mcL of each of the 2-fold dilutions. Consistency and reproducibilty are key here.

[yiams]

We would titer the antibody using gel anti-IgG cards. As stated in another reply, the key is consistency and reproducibility. If it reacts in gel then it should be titered with gel techniques. At least that's how we look at it.

[Mabel Adams]

If you are doing gel titers you need to have informed your OBs that the titer values in their books won't correlate to yours as far as clinical outcomes. Gel titers of 16 could cause unnecessary amniocenteses without this notification.

[LaraT23]

I agree with gel titers, you need to keep with the same method for comparable results.

[yolis76]

I also think that if you are going to perform Gel titers you need to make sure you make ALL the OBs aware, you are going to get MUCH higher titers with gel than with tube... that said, I put a policy in place recently dealing with this. We identify antibodies in Solid Phase. Any AB's that may need to be titered must first be tested NEAT in the tube as you would your titer. So, our titer SOP states we use 3 drops plasma to 1 drop RC, incubate for 1 hours at 37C, wash and add Anti-IgG. If it reacts in this test 1+ or greater, the tech must titer. If weaker, then I report the titer result as Less than 1.