Times To all: In fairness to Luminex, please let me make the situation in this laboratory clear. Our problems with the technology resulted from the following: We conjugated the beads ourselves with our choice of antibodies; we did not use the current bead preparation that is now commercially available; we were developing the assay in our spare time, and, perhaps most importantly, we did not inform the company of how unhappy we were with their product, even though they knew we were having problems. It is now my understanding that the biochemistry of attaching proteins or other substances to these beads is not uncomplicated. It requires perserverance and a substantial knowledge of protein (or other) chemistry to trouble-shoot problems. Luminex has kindly offered to refund our purchase price and we will gladly accept. They have also assured me that, in spite of the suggestion in the CAP survey article, they fully support the FlowMetrix technology they sold a few years ago. I would like to make a few comments, though. When Luminex presented this technology, it appeared to us to be a superior way (and an easier way) to measure substances that required some cumbersome and expensive techniques. We were very excited (as were research scientists here) about this technology. We are a core service facility and we see a broad range of sample types, including bacteria and yeast, cells from snails, pigs, cows, horses, mice, rats, dogs, monkeys and, of course, humans. In addition, to a variety of species, the sample site is also varied. Scientists want to look in blood, spinal fluid, guts, bladders, lungs, hearts, and maybe spit. Sometimes sample sizes are very small and this technology offered a way to measure substances in these samples. In retrospect, I can see that our efforts to use this technology in this setting were probably doomed from the start. A mix of biochemically-challenged flow cytometrists that were pressed for time, a technology that requires stringent preparation, and measurement in FUO (fluids of unknown origin) made it pretty much impossible to succeed. I think some of these reasons may also account for the dissatisfaction in the research labs that responded to the survey as well. I believe that the technology works very well when the sample is relatively homogeneous (human serum, for example), the manufacturer does the bead preparation under strict guidelines for reproducibility and performance in that kind of sample-- which may be no small task, and even design their own cytometer to collect the data. Certainly, the company's move towards these ends bears this out. There is certainly a place for this technology but I am not sure that at its current state of development that it is robust enough for our needs. To use our choice of substances in a variety of samples probably requires a fairly exhaustive development for each assay system. It is this developmental time that is most deterring to us and to the scientists that use our facility. It is our hope that manufacturers consider where and how their product will be used before they promote it. What may work in one system might be doomed in another. Knowledge of product performance where ever it is promoted is essential. Kathy -------------------------------------------------------------- Kathy Schell Supervisor, UWCCC Flow Cytometry Facility 600 Highland Ave. K4/535 Madison, WI 53792 Voice: 608-263-0313 e-mail: kschell@facstaff.wisc.edu