49 CFR §40.161

1. (a)Place a check mark in the “Test Cancelled” box (Step 6) on Copy 2 (or a legible copy of Copy 3-5) of the CCF and enter the reason on the “Remarks” line. If you do not have Copy 2 (or a legible copy of Copy 3-5), then enter “Test Cancelled” and the reason for the cancellation on a report in the format required under § 40.163(c).
2. (b)Report to the DER that the test is cancelled and the reason for cancellation, and that no further action is required unless a negative test is required (e.g., in the case of a pre-employment, return-to-duty, or follow-up test).
3. (c)You may only report a test cancelled because of a “rejected for testing” laboratory result when you are in possession of a legible copy of Copy 1 of the CCF. In addition, you must have Copy 2 of the CCF, a legible copy of it, or any other copy of the CCF containing the employee's signature. If you do not have Copy 2 (or a legible copy of Copy 3-5), then enter “Test Cancelled” and the reason for the cancellation on a report in the format required under § 40.163(c).