First, you passed your at home tests and they are 95-98% accurate. I think you are good to go as long as you abstain from smoking. Second, I do not know about comcast testing but they are most likely set at 50ng/ml which is standard. They will probably set you up at quest with an immunoassay and if you pass that its over. If you do not pass they will send your sample for a gc/ms test which will confirm the immunoassay. Have you tested your first void at home? This void will have the heaviest concentration of metabolites, If you pass that then you are good. If not then read up on the dillution sticky and do a mild dillute with about 40 oz of gatorade, skip the aspirin. Eat red meat starting 2 days prior to your test.