From Linda Stang, Alberta Health Services: George–hoping you or one of your participants has some advice for us. We run the American Diagnostica (now Sekisui) kit for activated protein C resistance ratio (APCRE) on two of our Stago STAR Evolutions. The issue we are having is that one of the instruments reads slightly overall higher ratios (more noticeable on the normal samples) than the other. So it is instrument dependent on how many of the samples need the factor V Leiden genotype done (we do not run samples for the genotype that fall into the normal reference range for the clot based assay). this is a relatively new phenomenon; we may have seen a slight difference before, but not to the degree that everyone is noticing that more genotypes are being done. The one thing we did check was the temp of the instruments: they have been made to correlate better but this did not show any improvement, in fact, may have made the situation worse. Any ideas about what to tweak next? Any participants run this APCRE assay on a STAR?
This is George’s June 23 message to Linda: Hi, Linda, my apologies for the delayed reply. I checked this with a colleague and their advice, like mine, probably parallels things you have already tried. There is little else you can do about your STAR’s calibration, so I would suggest you ask Stago to comp you an APCR kit and compare instruments using their kit. You may also ask your Stago service rep if he/she can tweak the electronic programming of the instruments. As you know, Stago employs an electronic adjustment that matches up their mechanical endpoint with the anticipated visual or optical endpoint. I’m only speculating, but perhaps this requires a tweak. Let me know whether these suggestions help, and how you eventually solve the problem. I’ll post his on Fritsma Factor when I get my laptop running again!
From Linda the next day. Thanks George, the service engineer is back again today and I will mention the electronic adjustment thing to him. I don’t think that Stago has an APCRE kit–at least not according to the US website (?)
And now from today, June 29, 2013: I have computer access while in Amsterdam, and have also discussed your problem with Precision BioLogic Inc head scientist, Dr. Ali Sadeghi Khomami, who tells me that, contrary to what I stated last week, there are numerous adjustments your service technician can make to match up your instrument outputs, including pipette volumes and temperatures, wash times, and others. I hope your tech is able to solve the problem, it is rather unlikely to be reagent or kit related.
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