A fresh negative test does not overturn a verified DOT positive. The split-specimen procedure checks the original specimen, and employers have specific duties when it is requested.
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Understand what the driver is asking for
49 CFR 40.171 gives an employee the opportunity to request split-specimen testing after notification of a verified positive or a refusal based on adulteration or substitution. The usual deadline is 72 hours after the MRO’s notification. The request goes to the MRO, verbally or in writing.
The MRO directs transfer of the retained split to a second HHS-certified laboratory and documents the request. An employee buying a new test at a collection center is not using that process. Be precise when recording a “retest” request so the employee is not sent to the wrong appointment.
Payment arrangements must not delay the required test
Under 49 CFR 40.173, the employer must ensure the required laboratory steps take place promptly after a valid request. The employer cannot demand advance payment or a reimbursement agreement as a condition of proceeding.
An employer may seek reimbursement under the applicable policy or agreement, but that is separate from ensuring the testing happens. Confirm the MRO has the necessary laboratory arrangements rather than leaving the employee to negotiate them alone.
Removal still applies while the result is checked
A verified positive or qualifying refusal requires immediate removal from safety-sensitive duties. The employer cannot wait for the written report or the split-specimen result before acting. A retest request is not an interim driving clearance.
The MRO explains the final result and any further required action. Split testing is not offered for an invalid result, and it does not resolve conduct-based refusal questions such as leaving the collection site. A late request may be considered by the MRO where documented unavoidable circumstances prevented it within 72 hours.
Illustrative case: a new negative result arrives first
A driver sends the carrier a negative result from a test purchased after the MRO reported a DOT positive. That document does not replace the original result or meet the split-specimen request requirement. The DER should keep the records distinct and direct questions about the original result to the MRO.
This example illustrates the process and is not a client outcome. If the violation remains, the employee needs the applicable SAP and return-to-duty steps. The later return-to-duty test follows successful compliance with SAP recommendations; it is not another name for split testing.
Where an evaluation is needed, find DOT SAP support. A SAP can explain evaluation and reporting arrangements, but cannot promise a reversal of a test result or make the employer’s return-to-work decision.
Frequently asked questions
Can the employer deny split testing because the driver cannot pay?
No. A timely valid request must proceed as required. Eventual reimbursement is a separate issue under the applicable policy or agreement.
Does a split test use a new urine sample?
No. It examines retained material from the original collection at a second HHS-certified laboratory.
Is the 72-hour request period a grace period for driving?
No. Required removal from safety-sensitive work remains in force while the verified positive or qualifying refusal applies.
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