Two different laboratories can have different methodologies, different sample preparation techniques, different cutoffs, different instrumentation, etc. THC is also a very sensitive compound that can break down rapidly in urine over time and temperature changes. In addition, although the result may state Negative it does not mean there was no THC present, it may mean that the THC concentration may not have been high enough to trigger a Positive result but it still is present. Different THC cut-off levels between labs could explain this as well.
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- Our patient is prescribed Lortab (hydrocodone) but their urine confirmation states Negative for hydrocodone but Positive for hydromorphone. The Dr. is ready to kick them out of the program, are we justified?
- I had my patients urine collected and sent to two different laboratories for comparison. The first laboratory came back with a Positive THC result however your laboratory came back Negative for THC. Explain this please.
- My patient is on a daily routine of Oxycodone but I see no Oxymorphone in their urine confirmation. Are they spiking their urine sample during collection?
- My patient swears they had recently used heroin but the confirmation results came back Negative. Are they lying?
- POC test screened Positive for certain drugs at collection but confirmed Negative. How?
- POC test screened Negative for all drugs at collection but confirmed positive by LC/MSMS. Why?
- Does the detection in urine of ETG and ETS rule out the possibility of hand sanitizer or mouth wash use?