Sorry for ressurecting this old post, but seemed the closest to this question....

I recently alarmed during a pat down after opting out.

Then alarmed at enhanced pat down..... and THEN carry on bag alarmed. Ultimately cleared and flew, about 15-20 minute delay. Treated decently by the senior agents, but it was my home airport and I am flying once or twice a week from there. (One or two of them knowing me, at least a mild recognitiuon, probably helped.)

So....I have both print outs from the last two scans....

(Annoyingly, it says "explosives detected", and -as TSA Ron points out- this is false. Or may be false- the machine only detects compounds 'consistent with explosives'...whatever.)

Here the thing(s)

1. Same bag flew and screened on Sunday and Monday. On tuesday it alarmed. Only change was fresh laundry, from a home washing machine...no different soaps used.

2. NO: lotion, new soap, nitroglycern/meds, fertilizer, golf, handguns, ammo, etc, etc. Nothing at all in my personal activities profile that would explain a compound that could be confused.

3. The swipe at the enhanced screen shows a positiive for 'substance E14+'. The next swipe, same machine, different agent, of the bag shows a positive for 'substance E6+'. ...???? The spectrum print outs are different for the two. (I do not have the print out for the first swab that was on a different machine.)

I'd scan and post, but I suspect the agents could get in trouble for me having this...and the event is linked to me. Anonomizing it will reduce it to nonsenseIMO

Not much online looking into the details, E6 vs E14 nor any of the other designators they use for unique detection limits.

And I'm flying tonight..same bag, albeit washed with detergent since the trip that had this issue. I'll leave a bit of time just in case.