The problem with you not having had a patch on for what appears to be at least 2 1/2 days prior to the test is that your body most probably had very little to no fentanyl left in your system. Fentanyl is transdermal, so it builds up slowly over a period of hours/days depending on your metabolism, until the steady blood plasma level is reached for the strength of the patches you are using. This could very well be why you showed up negative for fentanyl. If you had the test on the 23rd?, they could have sent it for gc/ms testing, and it can show up negative because the metabolites for the fentanyl would be below the tests threshold..and this could be a major problem, given that you have told them that the patches repeatedly aren't sticking and you are running out early.
Given that you sweat profusely and work around steam and high heat environments, it may be that the fentanyl patches are not the best choice in pain medication for you and it might be more reasonable to convert you to another oral pain medication in place of it. If you aren't dismissed because of the test results, it might be a good idea to talk to your regular PM doctor about the issues with the patches and about converting you to a pill form of a different pain med.
Sandi