Dilute Samples: Understanding DOT Testing Rules for Employers and Employees

In DOT-regulated drug testing, the issue of dilute samples arises when a urine sample appears overly diluted, making it difficult to determine accurate results. While not always indicative of tampering, dilute samples present unique challenges for both employers and employees. This blog explores the rules surrounding dilute samples, when recollection is required, and the importance of consistent policies.

What Are Dilute Samples?

A dilute sample is a urine specimen that contains unusually low concentrations of creatinine and other substances, making it appear watery or less concentrated. Dilution can occur for several reasons:

1. Excessive water consumption before testing
2. Attempted tampering to mask the presence of drugs
3. Medical conditions affecting kidney function

Recollection Options for Dilute Samples

DOT rules provide flexibility to employers regarding how they handle dilute samples. Here’s what you need to know:

No DOT Requirement for Recollection:
Employers are not required to recollect on dilute samples unless creatinine levels are extremely low.

Optional Recollection Policy:
If employers choose to recollect, they must include this requirement in their written policy and apply it consistently to all dilute samples.

1. Non-Observed Recollection: A recollection can be done without direct observation for standard dilute samples.
2. The result of the second collection is final—even if it’s also dilute, no further tests are required unless specific criteria are met.

Low Creatinine Levels Trigger Observed Testing:
If creatinine levels fall between 2 and 5 milligrams per deciliter, the MRO (Medical Review Officer) will instruct the DER (Designated Employer Representative) to conduct an immediate recollection under direct observation.

Less Than 2 Milligrams:
Samples with creatinine levels below 2 milligrams per deciliter are considered adulterated or substituted, indicating the sample is not human urine. This is classified as a refusal to test.

Why Employers Need Consistent Policies

Employers opting to recollect on dilute samples must ensure their policies are applied fairly and consistently.

Consistency Avoids Bias:
Employers cannot selectively require recollection for certain employees. If a recollection policy exists, it must apply equally to everyone.

Clarity in Policies:
Policies should clearly state:

1. Whether recollection will occur for dilute samples
2. Whether recollection will be non-observed or observed
3. How results of recollections will be handled

Refusal to Test:
Employees who refuse a required second test are committing a refusal to test, which carries serious consequences under DOT rules.

Final Thoughts: Handling Dilute Samples the Right Way

Dilute samples can complicate the drug testing process, but clear and consistent policies help maintain fairness and compliance. By understanding the rules and options for recollection, employers can reduce confusion and protect the integrity of their testing programs.

For Employers:
Define your approach to dilute samples in your policy, apply it consistently, and follow DOT guidelines.

For Employees:
Avoid excessive water intake before testing and follow all instructions carefully.

Need help drafting your policy or navigating DOT drug testing regulations? Let me know how I can assist!