[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: 49CFR40.93]

[Page 652-653]
 
                        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.  40.93  What criteria do laboratories use to establish that a specimen 
is dilute or substituted?

    (a) As a laboratory, you must consider the primary specimen to be 
dilute when:
    (1) The creatinine concentration is greater than or equal to 2 mg/dL 
but less than 20 mg/dL, and

[[Page 653]]

    (2) The specific gravity is greater than 1.0010 but less than 1.0030 
on a single aliquot.
    (b) As a laboratory, you must consider the primary specimen to be 
substituted when the creatinine concentration is less than 2 mg/dL and 
the specific gravity is less than or equal to 1.0010 or greater than or 
equal to 1.0200 on both the initial and confirmatory creatinine tests 
and on both the initial and confirmatory specific gravity tests on two 
separate aliquots.

[69 FR 64867, Nov. 9, 2004]