Drug Test Results: Screen vs Confirm, What Each Result Means and What Happens Next

Updated 15 Oct 2026 · By the DrugTestAnswers editorial team

You got an email that says your result is "non-negative" or "pending MRO review" and your stomach dropped. Breathe. A screening result and a confirmed result are two very different things, and understanding the difference tells you exactly where you stand and what to do next.

Two tests, two jobs

Think of the screen as a metal detector at the airport and the confirmation as the officer actually opening your bag. The screen is fast and cheap and built to catch anything that might be there. The confirmation is slow and expensive and built to prove what's really there.

Why the confirmation cutoff is lower

People are often confused that the confirmation cutoff is lower than the screening one. It's because the two tests measure different things. The immunoassay reacts to a whole family of related compounds, so its number is a rough total. GC-MS measures only the one target metabolite. The lower confirmation number isn't "stricter" in a sneaky way; it's matched to a more precise measurement. Full numbers are on our cutoff levels page.

What each result label means

• Negative: the screen was under the cutoff. Done. Most results stop here.
• Negative-dilute: negative, but creatinine and specific gravity were low. Some employers accept it; others order a retest, sometimes observed.
• Non-negative / presumptive positive: the screen didn't rule the drug out. The sample goes for confirmation. This is not a failed test yet.
• Pending: usually means confirmation or MRO review is happening.
• Confirmed positive: GC-MS found the drug above the confirmation cutoff.
• MRO verified negative: confirmed positive, but the doctor found a legitimate explanation such as a prescription, so it's reported as negative.
• MRO verified positive: no acceptable medical explanation.
• Invalid, adulterated or substituted: the sample itself failed validity checks.

Where false positives get caught

Immunoassays can cross-react. Commonly reported examples include certain cold medicines and pseudoephedrine on amphetamine screens, some antidepressants and antipsychotics, ofloxacin and other quinolone antibiotics on opiate screens, and efavirenz on THC screens. Poppy seeds can push morphine up, which is one reason federal opiate cutoffs were raised to 2,000 ng/mL. GC-MS sorts nearly all of these out because it sees the actual molecule.

That's also why an instant cup reading positive at a clinic shouldn't be the final word. Ask whether it will be lab-confirmed.

The MRO call

In regulated programs and many private ones, a Medical Review Officer reviews every confirmed positive before the employer sees it. Expect a call from a doctor's office. Pick up. If you can't be reached after reasonable attempts, the MRO may verify the result without your input. Have your prescription bottles or pharmacy printout ready. The MRO tells the employer only "positive" or "negative" in most cases, not your medical details.

Can you challenge a confirmed result?

Often, yes. Many programs keep a split specimen, a second sealed bottle from the same void. You can request that it be tested at a different certified lab, usually within 72 hours of the MRO notifying you, and you may have to pay. The split test only checks whether the drug is present (it doesn't re-apply the cutoff), so it's mainly useful if you believe the sample was mixed up.

How long each step takes

Negative screens: 24-48 hours from the lab. Confirmation adds 1-3 days, and MRO review another day or more. A week is not unusual for a confirmed result that needs a phone interview.

Know before you go

A home screen won't predict a lab's GC-MS result exactly, but it uses the same immunoassay principle as stage one, so it's a solid early warning. If you take regular medication, a good false-positive reference helps you speak the MRO's language.

A real-world example of how it plays out

Picture this. A guy takes a prescribed ADHD medication, goes for a pre-employment screen on Monday, and the lab's immunoassay comes back non-negative for amphetamines on Tuesday. The lab doesn't call his employer. Instead, it runs GC-MS on the same sample Wednesday and confirms amphetamine above 250 ng/mL. On Thursday an MRO calls him, he reads off his prescription details and the pharmacy name, and the MRO checks it. On Friday the employer gets "negative." From the employer's side, the result just took four days. From his side, he never actually failed anything, because the system did what it's designed to do.

Now flip it. Same timeline, but he has no prescription. The MRO verifies a positive, and the employer gets that result. At that point the screen vs confirm distinction no longer helps, because the confirmation is extremely reliable.

Instant cups at the workplace

Some employers use instant cups at their own office or a clinic. If one reads non-negative, a responsible program sends that cup's sample to a certified lab for confirmation before making any decision. If an employer acts only on an instant result, it's fair to politely ask whether a lab confirmation was done and to request one. Some states require confirmation before an employer can take adverse action, so asking costs you nothing.

Keep a short medication list

Before any test, write down everything you took in the last week or two: prescriptions, over-the-counter cold and allergy medicine, sleep aids, supplements, and anything unusual like poppy seed bagels or hemp products. You won't hand it to the collector, but you'll have it ready if the MRO calls.