Can tylenol (acetaminophen) with codeine show as coke in a drug test my sister in law to a drug test, she was taking tylenol (acetaminophen) with codeine, the test came out positive for cocaine, can this happen?

Codeine : Codeine is in the opiate class of drugs such as heroin, oxycodone, and morphine so it would cause a drug test to be positive for opiates. Codeine would not cause a test to be positive for cocaine.

Not likely: Most drug tests use a first test, TLC or thin layer chromatography, as an initial screen. This test is prone to cross-reaction or "false positive" results for some substances. Usually if the TLC is positive, a second test, gcms or gas chromatography mass spectroscopy is used to confirm. This test is much more specific for specific molecules and not likely to yield false positive results.

Cocaine is cocaine: If Cocaine is positive on a confirmatory urine drug screen (e.g.Lc/ms), 99.99% it is cocaine. Specificity for both screening & confirmatory urine tests for Cocaine is very high, thanks to its unique molecular structure. Even similar substances in the -caine class such as lidocaie, marcaine, etc. Do not cause a false positive Cocaine on a urine drug screen.