A random testing programme fails legally at the selection stage far more often than at the laboratory. If the selection is not genuinely random, or if a supervisor can influence who is picked, the programme is neither random nor defensible. Mobile collection is the practical answer for sites where sending people away is impractical, and it introduces its own requirements. This page covers both.
Random has to mean random
Selection must be made by a scientifically valid method, such as a random number generator applied to employee identifiers, so that every covered employee has an equal chance on every draw. Selections must be unannounced and spread reasonably through the year rather than clustered, and an employee selected must be tested promptly after being notified. What breaks a programme is discretion: a supervisor deciding who to send, or a manager choosing the timing to coincide with suspicion. That is not random testing, it is reasonable suspicion testing without the documentation reasonable suspicion requires.
The pool defines the programme
For regulated employers the pool is the safety-sensitive population and the annual testing rates are set by the relevant agency. For unregulated employers the pool is whatever your written policy defines, and defining it carelessly is the usual source of trouble: a pool that includes some job categories and not others needs a reason connected to the role, not to who management would like to test. Small employers commonly join a consortium precisely because a pool of three people cannot deliver a meaningful random selection.
Where mobile collection earns its cost
A mobile collector attends the workplace with the necessary equipment and the same custody and control procedure used at a fixed site. It removes travel time and, importantly for random testing, removes the gap between notification and collection during which an employee is unsupervised. For remote sites, shift operations, construction and transport depots it is often cheaper than the lost hours of sending people to a clinic. The collector still has to be trained in the correct procedure and the collection area still has to be properly secured, which is harder in a portakabin than in a clinic and is worth inspecting.
The policy has to exist first
Written policy before programme, always. It should say who is in the pool and why, what substances are tested for, what the selection method is, what happens on a positive, a dilute, a refusal and an adulterated specimen, and who makes the decisions. State law varies on random testing of unregulated employees, with some states restricting it to safety-sensitive positions, so the policy needs to be checked against the states you operate in rather than written once nationally.
Questions people ask about mobile drug testing
What makes a random drug test genuinely random?
Selection by a scientifically valid method giving every covered employee an equal chance on every draw, unannounced, spread through the year, with no discretion for supervisors over who is picked or when.
Can a manager pick who gets tested?
Not in a random programme. That is reasonable suspicion testing, which requires documented, articulable observations and a different process entirely.
Why do small employers join a consortium?
Because a pool of a handful of people cannot produce a meaningful random selection. A consortium provides a pool large enough for the method to mean something and administers the draws.
Is mobile collection as defensible as a clinic?
It can be, provided the collector is trained in the correct procedure and the collection area is properly secured. Those two are harder on site than in a clinic and are worth inspecting rather than assuming.