How can I accurately home test a family member for Oxycodone or Oxycontin use?

I have a family member currently recovering for severe Oxy abuse...7+ years. She had been snorting the pills daily and has roughly one month sober. Unfortunately I have reason to believe that she may be relapsing. I don't have a large enough budget to acquire a clinical test. Is there an accurate home test that could detect the possibly small amount of Oxy in her system? Keep in mind that she is snorting the pills and not ingesting them orally. Thank you for your help.