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DOT Regulations - 49 CFR Part 40
Subpart H—Split Specimen Tests

§ 40.181 What does the second laboratory do with the split specimen when it is tested to reconfirm a substituted test result?

December 18, 2025 19:14

As the laboratory testing a urine split specimen, you must test the split specimen using the confirmatory tests for creatinine and specific gravity, using the criteria set forth in § 40.88.

[88 FR 27646, May 2, 2023]

This information was copied from a federal government resource. Always verify the accuracy of this information against the most recent version of the Code of Federal Regulations: https://www.ecfr.gov/current/title-49/subtitle-A/part-40 or the Office of Drug & Alcohol Policy & Compliance: https://www.transportation.gov/odapc.

Articles in this section

§ 40.171 How does an employee request a test of a split specimen?
Section 40.171 Questions and Answers
§ 40.173 Who is responsible for paying for the test of a split specimen?
§ 40.175 What steps does the first laboratory take with a split specimen?
§ 40.177 What does the second laboratory do with the split specimen when it is tested to reconfirm the presence of a drug or drug metabolite?
§ 40.179 What does the second laboratory do with the split specimen when it is tested to reconfirm an adulterated test result?
§ 40.181 What does the second laboratory do with the split specimen when it is tested to reconfirm a substituted test result?
§ 40.183 What information do laboratories report to MROs regarding split specimen results?
§ 40.185 Through what methods and to whom must a laboratory report split specimen results?
§ 40.187 What does the MRO do with split specimen laboratory results?