As has been noted, there is variation in pregnancy testing, and this is mirrored in "standard" DOA screening. At the recent clinical toxicology network it was noted that there was a range of testing that covered the spectrum of
Immunoassay with workplace testing cut offs
Mass spec with validated workplace cut offs + validated in house cut offs set at pragmatic concentrations
Mass spec with validated "limit of detection" cut offs
Mass spec with "qualitative screens" ie, no defined concentration as to detected or not detected
So, there was a range of testing of 7 drug groups (immunoassay) to 1300 drugs ...
We all teach that, in general, a drug may be in the urine for about a week after use. However, this is based around the workplace testing cut offs. I do not know e.g. how long after regular heroin use you can still detect morphine at a LOD of 10 ng/mL
Hence in answer to your question, there is no uniformity across the UK, and, despite many of us having nice shiny LCMS or even HRMS, we are not helping clinically (depending on the question being asked by the testing ).
We are hoping to do a more structured survey soon, and then maybe we can decide as a profession, along with the clinicians, what and at at what concentrations we should be saying a drug is preset or absent
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