§40.90 What criteria do laboratories use to establish that a urine specimen is invalid?

Current as of Oct 29, 2026Last amended Jun 1, 2023Official text on eCFR ↗

(a) As a laboratory, you must use the invalid test result criteria for the initial and confirmation testing as required by the HHS Mandatory Guidelines, and you must use two separate aliquots—one for the initial test and another for the confirmation test.

(b) As a laboratory, for a specimen having an invalid result for one of the reasons outlined in the HHS Mandatory Guidelines, you must contact the MRO to discuss whether sending the specimen to another HHS certified laboratory for testing would be useful in being able to report a positive or adulterated result.

(c) As a laboratory, you must report invalid results in accordance with the invalid test result criteria as required by the HHS Guidelines and provide the numerical value that supports the invalid result, where appropriate, such as pH.

(d) As a laboratory, you must report the reason a test result is invalid.

Source: 73 FR 35970, June 25, 2008. Redesignated at 88 FR 27643, May 2, 2023

Compiled from the Electronic Code of Federal Regulations (eCFR), an editorial compilation and not an official legal edition of the CFR. The official text is the Federal Register and the annual CFR edition. §40.90 on eCFR.

Sections that cite this one

  • §40.159 What does the MRO do when a drug test result is invalid?