You can try a hair analysis. Years ago when I was a lab tech we collected them for pre employment physicals, but most for THC. They can show a sort of timeline. That might be an option. Did he repeat it? It could have been a bad test. Try going to your old one and explain what happened. If he can do a blood test he can get a numerical value and show that its been in your system continuously. I had one show up negative for a muscle relaxer that i had been taking for years(tested at outside lab). Dr. Knew it was wrong because he knew ME. Good luck.
Human factor - the "Labs" are production laboratories.
The lab I worked at utilized both gas chromatography and mass spectrometry - The U.S. Nuclear Regulatory Commission (NRC) & Other federal agencies had strict procedures - failure adhere could & sometimes did result in conviction & a prison sentence.
Despite the oversight & threat of prison - human error still inaccurate reporting.
The "Wee-B-Pee" urine screening labs are focused on the number of samples per/day and not have the same punishment for errors & lack quality control.
There should be transparency by the Provider & their "Chosen" lab - inform the POTENTIAL patient of quality controls - quality labs have a blank & known spikes. At the start of the tester's shift the test equipment is TESTED to determine if it can detect a blank - nothing present & if it properly measures the known spikes to prove it accurately can detect what it is testing for - THEN 10 (ten) client samples are tested. After every (10) client samples the test equipment is rechecked with blanks & spikes.
This is only the first line of quality control .
The provider should tell the prospective patient what random number is selected as their fail number.
One lab (as of January 2023) uses 17 Nanograms - any result over is a FAIL. (The absurdity is in October 2003 the cut-off for Federal work places was set to 2,000 ng /ml - from the previous cutoff of 300 ng/ml after it was determined that 300 mg/ml could not accurately differentiate poppy seed used in cooking OR caused by Heroin or Morphine abuse.
I believe the low cutoff level of 17 ng/ml used by the "provider's lab of choice" is merely a scam to re-test a large number of patients at $250 /each screen.
CASH IS KING
Typically an in office screen is done- then a urine sample is sent out for confirmation/quantity testing. The in office screenings can be false negatives/positives because of the baseline levels required for a positive result .
The testing done by outside lab is both a positive/negative result based AND shows actual levels of the metabolites of the medications you are prescribed as nano grams per milliliters- and is typically very accurate. These types of testing are gas chromatography and mass spectrometry- and reveals if meds are being taken as presctibed or not.
Another testing type could be used — that requires a blood level .
The big problem with urine screens is unless the same sample is sent out for bc/ms testing- results typically aren’t received until a week or so later if sent out -and there is no way to legitimately dispute results since most opiates clear the system within that time frame.