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Expired conjugated Antibodies? - (Jan/02/2010 )


I'm just wondering when conjugated ab's are too old to use? In my lab there's a big box with lots of expired ab's, and I would like to test some of them to see if my cells of interest express that particular marker at all.

I have antibodies that expired just one or two years ago and they works fine, but what about e.g. five years?

What will likely be the major problem with these old reagents? Decreased binding capacity or decreased fluorescence capacity?



what kind of conjugated ab? FITC expires quickly, but Alexa has a longer shelve time. so it really depends


Actually I just tried an antibody labeled with FITC that expired in 2005, and it seemes to work just fine!

According to several manufacturers, ab's should probably be useless after a couple of years, but now I doubt that.


Conjugated antibodies can be remarkably stable. I've used antibodies that were more than 5 years post expiration date without problems.

Of course some of those antibodies really were dead B) . Tandem-dye antibodies are the least stable-not a big surprise!


yeah even i ve used expired antibodies without any concerns except for decreasing the dilusions in certain cases!!!

-Pradeep Iyer-