Negative Dilute


Creatinine is a naturally occurring waste product found in all human urine, if a specimen is found to have no creatinine it is not human urine.

The following are the parameters that determine whether or not a specimen is normal or dilute:

[tabgroup] [tab title=”Normal Specimen”] Concentration of creatinine: Between 20 mg/dl and 250 mg/dl.                                       Specific gravity levels: Between 1.0030 and 1.0200[/tab] [tab title=”Dilute Specimen”] Concentration of creatinine: 5 mg/dl or greater but less than 20 mg/dl.                          Specific gravity levels: Greater than 1.0010 but less than 1.0030[/tab] [/tabgroup]


  • If a urine specimen falls outside of the normal range it does not necessarily mean that the result will be invalid.


What should an employer do?

  • If an employer falls under DOT guidelines please see the DOT regulations regarding negative dilutes:  
  •  Some find it helpful to understand the DOT’s response to negative dilute results as a benchmark for their own policy:
  • DOT regulations (49 CFR Part 40.197) allow the employer to make a decision to re-collect these donors one time under the following circumstances:


1. Such recollections must not be collected under direct observation.

2. You must treat all employees the same for this purpose.

3. You may establish different policies for different types of tests (e.g., conduct retests in pre-employment situations, but not in random test situations).

4. You must inform your employees of your policy regarding the actions taken after receipt of a negative dilute result.

5. You must treat the result of the test you directed the employee to take as the test result of record, even if it is dilute.

  • The decision regarding the treatment of negative dilute test results relies solely on the employer and the drug free workplace policy currently in place at the company. AMC can explain the meaning of a negative dilute result however we cannot give advice as to whether or not a re-collection should be taken.

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PLEASE NOTE: The following is presented as general educational information. It is not legal advice, either express or implied. Consultation with your legal counsel is recommended for all employment law matters.