If the employee is non-DOT regulated, then yes you may have a single specimen collection. But for those who are DOT regulated, you cannot. (Please see Part 40 below).

40.17 How does the collector prepare the specimens?

a. All collections under DOT agency drug testing regulations must be split specimen collections.

b. As the collector, you must take the following steps, in order, after the employee brings the urine specimen to you. You must take these steps in the presence of the employee.

1. Check the box on the CCF (Step 2) indicating that this was a split specimen collection.
2. You, not the employee, must first pour at least 30mL of urine from the collection container into one specimen bottle, to be used for the primary specimen.
3. You, not the employee, must then pour at least 15 mL of urine from the collection container into the second specimen bottle to be used for the split specimen.
4. You, not the employee, must place and secure (i.e., tighten or snap) the lids/caps on the bottles.
5. You, not the employee, must seal the bottles by placing the tamper-evident bottle seals over the bottle caps/lids and down the sides of the bottles.