Drug-test results use specific terms that describe what the test found and how the specimen met the program’s criteria. “Positive” and “negative” are not complete interpretations by themselves. The specimen, panel, test stage, cutoff, medical review, and governing rules all matter.
This hub explains common result categories and appropriate next steps. Return to Drug Testing: The Complete Guide for the full process.
Negative result
A negative result generally means that none of the reported analytes met the program’s criteria for a positive result. It does not prove that a person has never used a drug or that every possible substance was absent. The tested panel may not include the relevant drug, collection may have occurred outside the detection period, or the concentration may have been below the cutoff.
The meaning can also depend on specimen validity. Some programs report “negative dilute” separately and apply specific recollection rules.
Read What Does a Negative Drug Test Mean?
Presumptive positive
A presumptive positive means an initial screening test reacted at or above its cutoff. It is not automatically a final positive. Screening methods may recognize a group of chemically related substances, and medications or other compounds can sometimes affect the reaction.
In a high-consequence program, a presumptive positive should be handled under the applicable confirmation and review process. The FDA advises consumers not to take serious action on a preliminary positive home test before obtaining the laboratory result.
Read What Does a Presumptive Positive Mean?
Confirmed positive
A laboratory-confirmed positive means a specific drug or metabolite met the confirmation criteria. It is stronger analytical evidence than an initial screen, but the final administrative or clinical interpretation may still require more work.
In many workplace programs, a Medical Review Officer evaluates the laboratory result, contacts the individual when required, and considers legitimate medical explanations. A prescription does not automatically explain every result; the drug, metabolite, timing, documentation, and program rules must be evaluated.
Read What Happens After a Confirmed Positive?
Dilute result
A dilute urine specimen has creatinine and specific-gravity findings within a range defined by the applicable program. Dilution can occur for ordinary physiological reasons as well as intentional or unintentional high fluid intake. The classification should not be treated as proof of motive.
A negative-dilute result may trigger no action, a permitted recollection, or a required recollection depending on the program and laboratory values. An employer or agency should follow the governing rule consistently rather than improvise.
Invalid, adulterated, or substituted specimen
Invalid generally means the laboratory could not obtain a valid result under the required criteria, sometimes because of an unidentified interference, abnormal characteristic, or unresolved analytical problem.
Adulterated describes a specimen meeting defined criteria for an adulterant or abnormal characteristic. Substituted describes a specimen meeting defined criteria inconsistent with a normal human specimen. The exact definitions and response procedures depend on the governing program.
These terms are technical findings. They should not be assigned based only on color, odor, a single field observation, or assumption about intent.
Read Dilute, Invalid, Adulterated, and Substituted Specimens.
Cancelled test
A cancelled test is neither positive nor negative. It generally means a problem prevented the test from producing a result under the applicable rules. The reason may involve collection, documentation, transport, specimen condition, laboratory processing, or review. The program determines whether a new collection is required and whether it must be directly observed.
What to check when reviewing a result
- Whose specimen was tested, and how was identity verified?
- Which specimen and collection date are shown?
- Which drugs and metabolites were included?
- Was the result an initial screen or a confirmation?
- Which cutoff and method applied?
- Was specimen validity evaluated?
- Did an MRO or qualified clinician review the result?
- What policy, regulation, or court order governs next steps?
- Is split-specimen testing, retesting, record access, or appeal available?
Retesting and disputes
A repeat test is not always the same as testing the original specimen. Depending on the program, options may include confirmation of the original specimen, analysis of a retained split specimen by a second qualified laboratory, recollection of a new specimen, review of chain-of-custody records, or an administrative appeal.
Time limits may be short. A person disputing a result should request the applicable policy, preserve documents, use the designated review channel, and seek qualified medical or legal advice when consequences are significant.
Read Drug-Test Retesting, Split Specimens, and Disputes.
Results do not automatically prove impairment or misuse
A laboratory-confirmed positive establishes that the reported analyte met the test criteria. It does not automatically establish when the substance was used, the dose, the source, a substance-use disorder, or impairment at a particular time. Those conclusions may require additional clinical, behavioral, toxicological, or legal evidence.
Related guides
- Screening Versus Confirmation
- False Positives and False Negatives
- The Medical Review Officer
- Result Interpretation Guide
Sources
- SAMHSA: Workplace Drug Testing Resources
- SAMHSA: Federal Workplace Drug Testing FAQs
- FDA: Drugs of Abuse Home Use Test
Last evidence review: October 29, 2026.