I appreciate your query. Drug testing for nicotine actually measures its byproduct called cotinine. Its level in blood or urine indicates whether this cotinine has come from passive smoking or active smoking. Again, there are grey zone areas, and in such cases a re-test may be performed. In some cases direct nicotine levels are measured.
Nicotine patch may be categorized as ‘non-nicotine product’, but in reality it is not. The release of nicotine is slower through a patch and thus it is often medically used during the de-addiction process to overcome cravings and help a person quit smoking. In regular users of nicotine patch, the drug testing will be positive as an appreciable amount will build up.
Also, the cotinine level in blood would be directly proportional to the amount of exposure to tobacco, both active and passive and the the chronicity of the smoking history. It takes about two weeks for blood cotinine level in a chronic or regular smoker to drop to the blood cotinine level of a non-smoker’s level. So, in such individuals if a urine test is carried out, it will remain positive for cotinine for several weeks. Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.