A negative-dilute result means no drugs were found, but the urine was more watered down than normal human urine. Many health science programs don't accept it and require a retest, often at the student's expense.
What "dilute" means
Under the federal HHS guidelines, a lab reports a specimen as dilute when creatinine is at least 2 but less than 20 mg/dL and specific gravity is above 1.0010 but below 1.0030 (the guidelines state two overlapping ranges). (source) The federal MRO manual repeats the same criteria. (source)
What programs do with a negative-dilute
- Retest, often at your cost. William Jewell College: "A test result of negative dilute shall necessitate retesting. Retesting may be at the student's expense." (source)
- A deadline. Quinnipiac requires a repeat screen at the student's expense within five business days; a second dilute means switching to a method other than urine. (source)
- Treated as positive. Washington State University considers any result "dilute" a positive drug screening. (source)
- Serious consequences after repeats. NYU Meyers: after two successive dilute screens, the student can't attend clinical rotations or classes. (source)
For comparison, the DOT workplace rule says the retest, not the earlier test, becomes the result of record, and refusing the retest counts as a refusal. (source) Student drug screens for clinicals aren't regulated by the Department of Transportation, but schools and reviewing doctors often follow the same federal procedures. Washington State University's policy, for example, cites the federal MRO guidance manual.
What causes a dilute specimen
The federal MRO manual lists drinking large volumes of fluid right before the test, taking a diuretic, drinking a lot in hot weather, and some medical conditions such as diabetes and pregnancy. (source) Drink normally before your test, not extra.
Retesting with Drug Free Schools
Order a 10-panel ($40), 11-panel with alcohol ($50) or 12-panel ($55) and test at any Quest location: order a drug screen. Questions: call or text 901-517-7450.
Sources
- HHS Mandatory Guidelines, 82 FR 7920 (2017), Section 3.8
- SAMHSA MRO Guidance Manual, 2025
- 49 CFR 40.197, negative-dilute results
- William Jewell College nursing drug testing policy
- Quinnipiac University drug screen policy
- NYU Meyers substance use policy
- WSU College of Nursing drug screening policy
General information from public federal documents and published school policies as of September 2026, not medical or legal advice. Your program and clinical sites set the rules that apply to you.
Frequently asked questions
Is a negative-dilute a failed drug test?
It's negative for drugs, but many programs don't accept it. Some require a retest at the student's expense, and some, like Washington State University's nursing program, treat it as positive.
What causes a dilute urine sample?
Drinking large amounts of fluid right before the test, diuretics, heavy drinking in hot weather, and some medical conditions such as diabetes and pregnancy, according to the federal MRO manual.
How much does a retest cost?
Through Drug Free Schools, a 10-panel at a Quest location is $40, or $50 with alcohol.
Program director or clinical coordinator? See how programs track every student’s requirements in one place: take the 8-step tour, or get your own demo login. $30 per student, one time.