[Code of Federal Regulations]
[Title 49, Volume 1]
[Revised as of October 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR40.91]

[Page 652]
 
                        TITLE 49--TRANSPORTATION
 
          Subtitle A--Office of the Secretary of Transportation
 
PART 40_PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING 
PROGRAMS--Table of Contents
 
                   Subpart F_Drug Testing Laboratories
 
Sec.  40.91  What validity tests must laboratories conduct on primary 
specimens?

    As a laboratory, when you conduct validity testing under Sec.  
40.89, you must conduct it in accordance with the requirements of this 
section.
    (a) You must determine the creatinine concentration on each primary 
specimen. You must also determine its specific gravity if you find the 
creatinine concentration to be less than 20 mg/dL.
    (b) You must determine the pH of each primary specimen.
    (c) You must perform one or more validity tests for oxidizing 
adulterants on each primary specimen.
    (d) You must perform additional validity tests on the primary 
specimen when the following conditions are observed:
    (1) Abnormal physical characteristics;
    (2) Reactions or responses characteristic of an adulterant obtained 
during initial or confirmatory drug tests (e.g., non-recovery of 
internal standards, unusual response); or
    (3) Possible unidentified interfering substance or adulterant.
    (e) If you determine that the specimen is invalid and HHS guidelines 
direct you to contact the MRO, you must contact the MRO and together 
decide if testing the primary specimen by another HHS certified 
laboratory would be useful in being able to report a positive or 
adulterated test result.

[65 FR 79526, Dec. 19, 2000, as amended at 69 FR 64867, Nov. 9, 2004]