I have never used any street drug yet I keep testing low for meth

@robinmungle Welcome to Mayo Connect. You pose a very interesting question, and I'm going to try to give you an answer. If you are clean, maybe it is time to look at your environment. Second hand exposure can lead to a false positive.
Here are some things to consider -
Does anyone in your household, workplace or other places you frequently go smoke meth?
Do you have a roommate or child who uses or cooks meth, and comes home with contaminated clothing which you then handle?
If you live in an apartment building, is someone cooking meth in another unit?
Finally, a long shot - my daughter moved into a house that had been used as crash pad for meth users. (The local PD told her after she bought and moved in.) Fortunately, it wasn't cooked there. To clean it up, we tore out and discarded all carpet and window coverings. Then we washed, sealed and painted all the walls and ceilings.

Is this an employer mandated drug test? If so, you probably need to track down the cause.

Sue

@robinmungle

Your Metformin could be giving the false-positive. What over-the-counter medications are you taking? Antihistamines, decongestants and things like Vicks inhaler can give a false-positive. In your browser search engine type in “what medications can cause a false-positive for meth” . .. or you can type in “can metformin cause a false-positive for meth” or other medications you are taking .. over-the-counter medications too.

I've seen family test positive for meth when she used her albuterol inhaler

@sabosarah Welcome to Mayo Connect, where we share our medical journeys and try to help one another along the way.
It is really scary and unfortunate when false positive drug tests happen to people, but I can't find any evidence that albuterol alone can cause a positive meth test. There a many other legitimate medications that a person might use for asthma that can cause this; maybe she used one of those in addition to her inhaler?
Sue

You’re around someone that has done it without you knowing. It can be eaten or swallowed without you knowing also. I have heard of people giving methamphetamine to others without them knowing it’s crazy and it makes no sense. Or maybe you’re around somewhere it has been made.