From Sheila Minor: We are currently using the Chromogenix Coatest APC Resistance VS kit for APCR testing. Chromogenix provides 1 set of level 1 and level 2 controls in each kit. The instructions state that the controls may be refrozen one time at –20 C or colder in their original vials. That would be fine if we used 1/2 kit for each run, but our volume of patients dictates that we use the kit for 1 month. We have been aliquoting the level 1 after the initial use into three additional aliquots to use weeks 2, 3, and 4. We have also been using Stago System N control simultaneously and generate enough data to use it for level 1 quality control. The problem is for level 2, System P is not factor V Leiden mutation positive, so we prepare an in-house pool of known factor V Leiden positive patient plasmas for our level 2 quality control. Chromogenix does have level 1 and 2 quality controls available outside their APCR kit, but they are quite expensive. One box of their quality controls would only last 10 weeks, if we follow their insert and freeze only once in its original vial. Do you have any recommendations for the appropriate material to use for APCR controls?
Hello, Sheila, and thank you for your question. In the interests of objectivity, I seldom promote the products of my sponsor, but this is too good an opportunity to ignore. Precision BioLogic Inc. offers CRYOcheck APCR Positive Control, which is a quality product that is shipped frozen. You may select the link I’ve provided for product information and to reach a representative and place an order. I hope this helps.
These sorts of controls tend
These sorts of controls tend to be very stable frozen. All you have to do is to validate after thawing that freezing in aliquots provides similar results to material frozen in the original vial and you will have your answer. Indeed, the Precision BioLogic Inc samples come frozen, and they are quite stable. If you want to freeze/thaw on more than one occasion, you will just need to verify that this is OK.