I've never seen an at home test but from my days working for lab corp I know it exists like you said, they can test for metabolites of anything.
That being said it shouldn't show up in a standard 6-panel (with Benzos obviously in
cluded) despite it metabolizing into meprobamate (which although very similar technically is not a benzodiazepine) & also something called carbamate. Since this was a field of expertise of mine for awhile many moons ago my friend I can tell you & others what most benzo urine screens are looking for (or atleast the standard 6-panel test):
- Oxazepam (Serax, Valium, Prazepam, Restoril)
- Nordiazepam (Valium, Restoril)
- α-hydroxyalprazolam (Xanax)
- Conjugated glucornides in urine or serum (they constitute a major proportion of the metabolites of many phenols, alcohols, and carboxylic acids: aka many benzos and booze obviously)
When any of these show up, particularly the first 3 then it is a definite positive. Conjugated glucornides in abnormal amounts can be caused by kidney excretion problems rarely but they can tell by other urine features if this is the case. Generally in this case the drug testing company will show a positive which can be disputed by the costly GS/MS test and gas spectroscopy WILL usually show the metabolites responsible (although a few: clonazepam, bromazepam, & triazolam) require testing of the glucuronide sample by reverse-phase liquid chromatography-tandem mass spectrometry in urine samples in these very hard to catch benzos.
Klonopin/Rivotril shows up as 7-aminoclonazepam, Bromazepam as 3-hydroxy-bromazepam, Halcion as
α-hydroxytriazolam. More than likely a lab will very very VERY rarely go this far and if you have these benzos the GS/MS likely won't reveal them from a 6-panel urine screen. A hospital of course will go this far ($) and find the culprit.
Soma (Carisoprodol) is hard to detect though. Meprobamate as well (especially since it is SO old and doesnt chemically fit the muscle relaxants included in a 10+ panel or benzos included in a 6-panel), has no active or tested for metabolites AFAIK and wont show up in even a 12-panel. Oddly though Soma, in a mall percentage of the population
will show up as Morphine as all things but if it does order a GS-MS to disprove this easily because even today Carisoprodol won't easily show up (if it ever has) in spectrometry testing.
Sorry to go off track man, I'm a pharma nerd. Now something that tests for 46 substances (this sounds like a probation test, no?) will indeed show Carisoprodol as well as things like Quetiapine (Seroquel) etc. and are usually used to ensure someone is taking their medicine at the correct level or at all.
In the research I've done in the past like 40 minutes I can't find any sort of OTC Take Home Soma drug tests.
Hope I've helped brother. GL.