I can’t speak to this as it hasn’t happened to me. But to your question about testing, there are other tests out there that can verify drug tests either via blood testing or urine. It can be worthwhile to seek testing through a primary care provider or even an emergency room. There’s a chance the initial test was a false negative, and subsequent tests might be helpful.
Vyvanse, while long-lasting, can clear out of your system within 24 hours. So if your child missed a dose it is likely that the drug test would come up negative. Providers should realize that and have asked follow-up questions.
Also, typically there is no physiological withdrawal from Vyvanse. If so, it’s not typically problematic or concerning. Of course individual experiences differ. Typically the Vyvanse works for 10-12 hours and then is out of the system anyway.
I’d advise the child to petition the clinic for a review of the case or to speak with another provider.
Drug testing is not perfect and it is humiliating. As an adult with ADHD I experience this myself. However, it is also a necessary part of the process now due to prescribing guidelines and clinics being concerned about misuse and liability. Hopefully there can be some resolution.