Start With a Written Policy
Before any test is conducted, your drug-free workplace policy needs to be in writing, distributed to all employees, and acknowledged with a signed receipt. The policy should clearly state which employees are subject to testing, which substances are covered, what types of testing will be conducted (pre-employment, random, post-accident, etc.), and what the consequences of a positive result or refusal to test will be.
For DOT-regulated employers, the policy must also comply with the applicable DOT agency's regulations. For non-DOT programs, the policy is your primary legal framework — make it specific and consistent.
Define Who Is in the Testing Pool
A random testing pool is the group of employees eligible for random selection. For DOT programs, only safety-sensitive employees belong in the pool, and the rules are clearly defined by each agency. For non-DOT programs, you can define the pool yourself — but the definition must be applied consistently.
Every employee in the pool must have an equal chance of being selected at each draw. You cannot exclude someone from the pool based on seniority, job performance, personal relationships, or any other non-regulatory reason. Inconsistent pool management is one of the most common sources of legal challenges to random testing programs.
Use a Truly Random Selection Method
The selection process must be genuinely random — meaning each individual's chance of being selected is statistically equal and cannot be predicted in advance. A supervisor pulling names from a hat does not meet this standard. Acceptable methods include computer-generated random number selection and third-party consortium management, where a service provider manages the selection pool on your behalf.
For DOT programs, FMCSA currently requires a minimum annual random testing rate of 50% of the pool for drugs and 10% for alcohol. Other DOT agencies have their own rate requirements. Non-DOT programs can set their own rates, though higher rates generally provide stronger deterrence.
The employee should not know they've been selected until they are notified to report for testing — and that notification should require immediate reporting. Any delay reduces the integrity of the test.
Notify and Test Without Delay
Once an employee is selected, notification should be immediate, and the employee should proceed directly to collection. A selected employee who is allowed to go home, complete a task, or delay reporting gives the testing a predictability that defeats the purpose of random selection. Document the time of notification and the time of collection arrival.
Mobile testing is particularly useful here — instead of sending an employee offsite, the collection can happen at the worksite with minimal disruption and no unsupervised travel time between notification and testing.
Document Everything
Maintain records of the selection dates and method, who was notified, when they reported, the test results, and any follow-up actions taken. For DOT programs, recordkeeping requirements are specified in Part 40 and the applicable agency regulations. For non-DOT programs, documentation supports your ability to defend any employment action taken based on test results.
Consider Using a C/TPA
A Consortium/Third Party Administrator (C/TPA) manages random testing pools on behalf of employers — particularly useful for small employers who may not have enough employees to generate statistically meaningful random draws on their own. C/TPAs handle selection, notification records, and often coordinate collection services as well.
If you're setting up a random program for the first time, working with a C/TPA alongside a qualified collection provider takes most of the administrative burden off your organization while keeping the program defensible.