Fast migration in RNA Bioanalyzer assay

[antoinefelden]

My latest RNA Bioanalyzer runs produced unexpected results, with migration time being reduced for both the ladder and the samples, see attached profiles for comparison (below in this order: abnormal ladder and an example of a sample in that run, normal ladder and the same sample).
I tried different gel preparations, and got similar results, which I believe affects proper quantification (but maybe still okay to check RNA integrity?). I've seen explanations for slow migrating fragments, but I haven't seen reports of what I have. Note that it's insect RNA, which is why there is only one single peak apart from the marker.

Does anyone ever had that problem? Cheers!

[pmiguel]

Vice-versa, I should think.

I've never seen this.
But if your ladder peaks don't resolve I don't think you can get a RIN score at all.
As long as your spike-in marker is there you could get a usable concentration -- well absolute concentration, the molarity figures will be wrong. But this all presupposes that the Agilent Bioanalyzer "Expert" software will even deign to give you any information without a ladder.

Are you sure you used the right gel mix? If you did and the parameters (run voltage, etc.) seem similar between your good and bad run, you might want to contact Agilent Tech support.

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Phillip