i was able to find this faq on concentras web site:

3. Will I have to empty my pockets and leave personal belongings outside the collection area while I take a drug screen? How will I know they are secure in my absence?

You are allowed to keep your wallet with you during this procedure. Lockboxes or locking drawers are available to secure other valuables. For the best security of your valuables, we recommend that you bring only the signed Employer Authorization for Treatment Form and your photo ID with you.