Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Drug and Alcohol Testing

In This Section

DOT Rule 49 CFR Part 40 Section 40.201

Subpart I—Problems in Drug Tests § 40.201 What problems always cause a drug test to be cancelled and may result in a requirement for another collection?   As the MRO, you must cancel a drug test when a laboratory reports that any of the following problems have occurred. You must...

DOT Rule 49 CFR Part 40 Section 40.199

Subpart I—Problems in Drug Tests § 40.199 What problems always cause a drug test to be cancelled?   (a) As the MRO, when the laboratory discovers a “fatal flaw” during its processing of incoming specimens (see §40.83), the laboratory will report to you that the specimen has been...

DOT Rule 49 CFR Part 40 Section 40.197

Subpart I—Problems in Drug Tests § 40.197 What happens when an employer receives a report of a dilute urine specimen?   (a) As the employer, if the MRO informs you that a positive drug test was dilute, you simply treat the test as a verified positive test. You must not direct the...

DOT Rule 49 CFR Part 40 Section 40.195

Subpart I—Problems in Drug Tests § 40.195 What happens when an individual is unable to provide a sufficient amount of specimen for a pre-employment follow-up or return-to-duty test because of a permanent or long-term medical condition?   (a) This section concerns a situation in which...

DOT Rule 49 CFR Part 40 Section 40.193

Subpart I—Problems in Drug Tests § 40.193 What happens when an employee does not provide a sufficient amount of specimen for a drug test?   (a) If an employee does not provide a sufficient amount of specimen to permit a drug test (i.e., 45 mL of urine in a single void, or 2mL oral...

DOT Rule 49 CFR Part 40 Section 40.191

Subpart I—Problems in Drug Tests § 40.191 What is a refusal to take a DOT drug test, and what are the consequences?   (a) As an employee, you have refused to take a drug test if you:   (1) Fail to appear for any test (except a pre-employment test) within a reasonable time,...

DOT Rule 49 CFR Part 40 Section 40.185

Subpart H - Split Specimen Tests§ 40.185 Through what methods and to whom must a laboratory report split specimen results? (a) As the laboratory testing the split specimen, you must report laboratory results directly, and only, to the MRO at his or her place of business. You must not report...