August 9, 2001
Federal Register Vol. 66
Pages 41996 - 42036

Notice of Interpretation:
April 22, 2002
Federal Register Vol. 67,
Pages 19615-19616
Primary Topic: FTA/USCG regulation applicability to ferry boats.

The need for the change became evident at a recent conference where technical experts disagreed on the minimum creatinine standard that should be used to determine if a specimen is substitute. Previously, the standard used in the DOT drug testing procedures (49 CFR Part 40.93(b)) was a creatinine concentration of less than or equal to 5 mg/dL and a specific gravity of less than or equal to 1.001 or greater than or equal to 1.020. This standard was based on studies by the HHS and constituted the best scientific information available at the time the DOT rule was published on August 1, 2001. Since that time, additional information has become available that puts this standard into question including a small number of cases in which individuals may have legitimate medical or physiological explanations for producing specimens with lower levels of creatinine.

This criterion is important because it is the measure used to determine if an employee’s specimen is substitute, and therefore, whether it constitutes a test refusal with resulting consequences. The intent was to establish the standard at a level that would eliminate the possibility that an individual could naturally produce such a specimen and thus, would provide evidence of substitution. Recent evidence indicates, however, there is a relatively small number of individuals who are capable of producing creatinine concentrations below the previous standard.

Experts agree that the standard should be lowered. The level should be low enough to ensure that individuals are not unfairly charged with substitution, however, the level must be high enough to identify individuals that substitute specimens to evade detection of drug use. While awaiting HHS guidance, the DOT decided to publish the interim final rule setting forth the following four basic provisions.

1. Laboratories are directed to report to MROs the creatinine and specific gravity quantifications for all DOT specimens that meet the regulatory substitution criteria (§40.93).
2.  Laboratories must provide quantitative values only when the concentration is above their minimum detection limit. Any reading below the minimum limit must be reported as “creatinine not detected.”
3.  If a creatinine level of a specimen is less than 2mg/dL or “creatinine not detected,” the MRO must report the specimen as “substituted.” If a creatinine level of a specimen is greater than or equal to 2mg/dL, but less than 20mg/dL, the MRO must report the specimen as “dilute” and negative or positive.
4.  If a specimen has a creatinine level greater than or equal to 2mg/dL but less than or equal to 5 mg/dL, the MRO must also direct the employer to require the employee to undergo an unannounced immediate recollection under direct observation and the employer must make sure the recollection takes place.

The rule did not change regarding specimens with creatinine levels above 5 mg/dL, but less than 20 mg/dL. In these cases, the employer determines whether to require a retest as a matter of policy. If negative dilute retests are required under this threshold, they may not be performed under direct observation (§40.197).

Laboratories are not currently required to conduct validity testing as part of the DOT testing program, but those that do, must follow the current standard. As with the previous rule, any individual that provides a specimen below the current standard (i.e., less than 2 mg/dL) has the ability to challenge the substitute determination by demonstrating that there is a legitimate medical explanation for the result following the procedures outlined in §40.145.