We were validating a new H1N1 protocol using samples from the state lab and I had one result that didn't match the state's result on the first run. It worked fine on repeated runs (re-extraction then RT-PCR). I believe this shows PCR inhibition, but I am not sure. Pre-amplification, the graph is supposed to be flat, but this has a downward slope and a late amplification curve that didn't pass the program's Ct (so it was resulted as "negative"). After a repeat the sample was strong positive which agreed with the state's results. We are using BD's software on the Cepheid Smart Cycler. Extraction was on the Qiagen QiaCube.
Any idea what could be going wrong with this one result? I want to be sure of what it is so that our techs will know to repeat the test if the curve looks like this. Thanks for the help.
Edited by eak435s, 01 March 2010 - 10:32 AM.