A collector may shake the specimen for the purpose indicated in the DOT Collector Guidelines (Jan 2018) with the assumption that they know what they’re looking for (they’ve had training to distinguish the differences) – and they should do so only when it is in a sealed container. Shaking might indicate excessive foam which would be suspicious leading to a second direct observed collection. Shaking might also indicate no foam and no bubbles which would be suspicious that synthetic urine was used, and this would lead to a second direct observed collection. Ongoing specimen collector training is always recommended.
The DOT Collector Guidelines (Jan 2018) do not mention shaking in the procedures for inspecting the specimen; however, the following statement is included:
The collector must inspect the specimen for unusual color, presence of foreign objects or material, or other signs of tampering or adulteration. If it is apparent from this inspection that the employee has adulterated or substituted the specimen (e.g., the specimen is blue, exhibits excessive foaming when shaken, has smell of bleach), a second collection using direct observation procedures must be conducted immediately.
There seems to be a discrepancy. The Office of Drug and Alcohol Policy and Compliance (ODAPC) has indicated that they will address this in the next Collector Guidelines.