Hi Dr. Markert,

I've always had really good results with Millipore's Luminex multiplex kits (assuming you have the dedicated instrument), however, I've really only used them for human/animal serum and cell lysates. Their applications specialists are awesome and can give you really solid advice about whether or not their kit will work. They also have pretty good academic discounts. The only problem, which is the problem with multiplexing in general and not Millipore specifically, is the reagent compatibility. This has always been a limiting factor in how many analytes I can "plex" together and I've never been able to get more than 13 at once despite the theoretical ability to have 100+.

On the other hand, after a bad experience with Invitrogen, now Life Technologies, I swore I would never work with them again, even though I assume they have fixed the issue by now. About 5 years ago I found that I could not get even remotely similar concentrations using the lab's internal control. Basically, we got a stock of stripped human serum and had spiked it with known concentrations of various biomarkers and then subsequently analyzed it with about 5-10 kits from different companies to validate it. the lot of their kits worked fine the first time but then several months later we reordered and they only had a new lot. Suddenly, out control was off by about 50% even though the kits controls were fine. Turned out, their validation procedure only referenced the previous lot, not a reference lot, and only required their validation controls be within 10% of the previous lot. In the intervening months they had made about 15 new lots of this kit and each time the validation was a few percent higher, but less than 10%. The net effect, however, was about a 50% drift. Realizing their error they gave us a full refund on all the kits we had used from them, but it did nothing to replace the wasted human sample from the now dead cancer patients and the 14 months of work analyzing the thousands of samples.

ELISA wise, I really like PeproTech's kits. Their development kits are dirt cheap and I have never had a single problem with their antibodies.

Hope this helps, and sorry for the long story, it still bothers me to this day when I think about it.

-Zack

Thanks Zack, this is exactly the kind of insight I'm seeking. Sorry to hear about your previous headaches!