If a line were to be so faint that a given tech wasnt sure how to interpret it (or even end up interpreting it as a 'non-negative') the sample would undergo the confirmation GC/MS just to be sure.

Even if an untrained tech were to misinterpret a faint line as a "non-negative" and the sample was referred to the GC/MS for confirmation, the sample would come back as a negative.

As far as your pic goes, I can see the line clearly - and thats without "blowing up" the pic or using magnifying devices. Its a negative.

A properly trained tech would utilize this rule of thumb: If it can be photocopied, its a line.
Burnt Toast Reviewed by Burnt Toast on . Some clarification about neg results Okay, so I understand that even a faint line is considered to be negative, but how open to interpretation is that? What is a "faint" to one lab tech be considered "preliminary positive" to another? I'm curious as to what people (especially those with experience) know about this. I took a DOT test and the morning before I took a test with first void and there was a faint line... then the day of my test I used my third void of the day for my actual DOT test, but then next void I tested with a Rating: 5