Negative Dilute Drug Test Result

23 Nov 2014

Negative Dilute Drug Test Result – Confused, what does this mean?

Many times employers get back a negative dilute drug test result and are often confused.  What does it mean that the specimen is negative dilute?

Perhaps the donor drinks a lot of water, perhaps the donor is trying to cheat the test.

When the lab reports a specimen as dilute, there are certain levels of creatinine and specific gravity that determine that the specimen may be dilute.  This basically means that the donor consumed a larger quantity of water before providing the urine specimen.  This may be normal as many folks drink a lot of water for health reasons or because of a fear of not being able to urinate at the time of the drug test specimen collection.  This may be abnormal as perhaps the donor is drinking an excessive quantity of water in an attempt to cheat on the drug test.  So there is a little bit of “gray” area concerning specimens that are reported as dilute.

First and foremost, if the report from your Medical Review Officer is Positive Dilute, the results is Positive and the company should follow policy for the Positive result.  The indication that the specimen was dilute may be interesting, but it is not relevant to the handling of the positive test result.   

For negative dilute results, the first question is whether or not the testing program is a regulated program – Federal employees or DOT drug testing.  If it is a regulated testing program the following guidelines apply:

In the regulated drug testing program negative dilutes are handled in one of two ways depending on the creatinine levels.

  1. When specimens have creatinine levels of 5 mg/dl or greater but less than 20 mg/dl and Specific Gravity greater than 1.0010 but less than 1.0200, this is a negative dilute and the employer should have a policy on how to handle this situation.  The MRO drug test result report will simply state Negative Dilute. The policy should either be to accept the result as is or to have the donor go for a second collection.

  2. When specimens have creatinine levels of greater than or equal to 2 mg/dl but less than 5 mg/dl; Specific Gravity less than or equal to 1.0010 the medical review officer (MRO) will report the results as negative dilute with a requirement that the donor go for a second collection under direct observation.  DOT rules (49 CFR Part 40.197) allow the employer to make a decision to re-collect these donors one time under the following circumstances:

a)      There is a policy statement in place before the fact that allows the practice.

b)      All employees are treated equally.

c)      The re-collections are not observed re-collections.

d)      Only one re-collection is allowed, and the result of the second collection is the result of record, even if it is another negative, dilute.

e)      The decision to re-collect may vary by reason for test. In other words, an employer may decide to re-collect all pre-employment dilute negatives, but not random dilutes, or vice versa.

Sample policy language for regulated drug testing programs is included at the end of this article.

NON – DOT Negative Dilutes

In non-regulated drug testing programs, the decision on how to handle the Negative Dilute drug test is an employer decision.  It is highly recommended that a policy is developed in advance on how to handle these results.  Sample policy language for non-regulated or Non DOT drug testing programs is included at the end of this article.

A dilute specimen, by definition, is a urine specimen that has a creatinine of greater than 5 mg/dl or less than 20 g/dl and a specific gravity is less than 1.0010 (or greater than 1.0200). These 2 tests are routinely performed on every urine sample that is tested at the Lab. If the specimen meets the above 2 criteria, it is reported as a "Dilute specimen". When a urine specimen is "dilute", it is possible that drugs in their system may not be detected. We recommend that an employer have a section in their drug testing policy stating that another specimen be collected as soon as possible with minimum advance notice, this will help prevent false negative results. However, the employer may also elect to accept the negative results with the notation "dilute" from the lab. The company policy should be consistent in all cases.

As with DOT testing, there is a highly suspicious level of dilution which would be where the creatinine levels are greater than or equal to 2 mg/dl but less than 5 mg/dl; Specific Gravity less than or equal to 1.0010 the medical review officer (MRO) will report the results as negative dilute with a recommendation that the donor go for a second collection under direct observation.  It is not recommended that a non-regulated employer required direct observed collections unless there is a significant concern for safety relative to the tested group.

National Drug Screening recommends for negative dilute specimens for non-regulated employers to require for both applicants and employees a second collection with little advance notice and instructions to not drink an unusually large quantity of fluids before the testing.  For applicants the second test would determine eligibility for employment and should be negative, not negative dilute.  For employees, perhaps a supervisor should escort the employee to the test to insure that large quantities of fluids are not consumed.

Non-DOT Policy Language Recommendations

DILUTE SPECIMEN

If the MRO informs the Company that a negative test was dilute, the Company may take the following action depending on Company policy and/or guidance provided by the MRO:

(1)    If the MRO directs that a recollection take place (i.e., because the creatinine concentration of the specimen was equal to or greater than 2mg/dL, but less than or equal to 5 mg/dL), the Company will do so immediately. Failure of the employee or applicant to submit for this recollection is classified as a refusal to test.

(2)    Otherwise (i.e., if the creatinine concentration of the negative dilute specimen is greater than 5 mg/dL), the Company will for existing employees:

  1. Accept the result as is OR;
  2. Require the employee for a retest upon immediate notification and be escorted by a supervisor.

(3)    Regarding a negative dilute (greater than 5 mg/dL on an applicant, the Company will:

  1. Accept the negative results as is OR;
  2. Require the applicant to retest within 24 hours and provide instructions to applicant on how to avoid a dilute specimen.


NOTE: The Company will treat all employees the same for this purpose. The Company may, however, establish different policies for different types of tests or employee categories (e.g., conduct retests in pre-employment situations, but not in random test situations). The Company will inform its employees in advance of its decisions on these matters.

When a retest is required after a negative dilute specimen, the employee or applicant will be given the minimum possible advance notice that he or she must go to the collection site. Instructions will be provided on how to avoid a dilute specimen.  The result of the retest will be considered the final result, not the result from the first test.   

If an employee declines to take a retest required because of a dilute specimen, the action will be considered a “refusal to be tested” and will be treated the same as a confirmed and verified positive result.  The offer of employment will be rescinded if an applicant refuses to take the retest because of a dilute specimen. 

DOT Policy Language Recommendations

DILUTE SPECIMEN

If the MRO informs the Company that a negative test was dilute, the Company may take the following action depending on Company policy and/or guidance provided by the MRO:

(1) If the MRO directs that a recollection take place under direct observation (i.e., because the creatinine concentration of the specimen was equal to or greater than 2mg/dL, but less than or equal to 5 mg/dL), the Company will do so immediately. Failure of the employee or applicant to submit for this recollection is classified by the DOT as a refusal to test. 

(2) Otherwise (i.e., if the creatinine concentration of the negative dilute specimen is greater than 5 mg/dL), the Company will for existing employees:

  1. Accept the negative dilute result as is, OR
  2. Require the employee for a retest upon immediate notification and be escorted by a supervisor.

(3) Regarding a negative dilute (greater than 5 mg/dL on an applicant, the Company will:

  1. Accept the negative dilute result as is, OR
  2. Require the applicant to retest within 24 hours and provide instructions to applicant on how to avoid a dilute specimen.


NOTE: The Company will treat all employees the same for this purpose. The Company may, however, establish different policies for different types of tests (e.g., conduct retests in pre-employment situations, but not in random test situations). The Company will inform its employees in advance of its decisions on these matters.

When such a retest is required after a negative dilute specimen, the employee or applicant will be given the minimum possible advance notice that he or she must go to the collection site. Instructions will be provided on how to avoid a dilute specimen.  The result of the retest will be considered the final result, not the result from the first test.  For current employees required to submit to a return-to-duty test or follow-up test (both of which under DOT regulations must render a negative test result) a second directly observed collection resulting in a negative dilute urine test result will render the final result a “negative” test; and an applicant with a second directly observed negative dilute urine test result will not be eligible for hire under the Company’s uniformly enforced policy. 

If the employee declines to take a retest required because of a dilute specimen, the action will be considered a “refusal to be tested” and will be treated the same as a confirmed and verified positive result.  The offer of employment will be rescinded if an applicant refuses to take the retest because of a dilute specimen.