what could affect a blood drug test come back neg when taken

[vickiecarithers]

been taking Adderall valium and oxycodone for 12 years all drug tests have shown compliance. now I got a false

neg and cant get medicine when I took them as prescribed. what could cause that? tried cbd oil but nothing else, the blood test said I didn't take the valium and adderal and a small amt of oxycodone. I took them all that am . why is it wrong?

[backhurtz]

It's not wrong, since you only took them that morning, the levels were too low in your bloodstream to be detected, which means you were below theraputic/expected levels, and could not be taking them consistently on a regular basis, unless they are prescribed as needed.
No one should think they can pass a test simply by taking these types of medications one time, or a few hours before they expect to be tested and get the correct levels.
Current pain management compliance testing looks at the whole picture- presence of expected/prescribed medications, expected therapeutic levels-(is the patient taking the correct dosage, too little, or too much), as well as any illegal/illicit drugs , marijuana/thc, alcohol, and even tobacco in some practices.
These tests are very specific, and reveal far more information than they did previously.