Sertraline (Zoloft) and False Positive Benzo Drug Tests

Yes, sertraline (Zoloft) can make a urine drug screen read positive for benzodiazepines when no benzodiazepine is in the sample. The FDA-approved prescribing information for Zoloft says so directly: false-positive urine immunoassay screens for benzodiazepines have been reported in patients taking sertraline. The result is only a presumptive screen. A lab method that identifies the actual molecule settles it.

This guide is for people who take sertraline and face a drug test, and for the clinics, employers and testing programs that have to read the result. It explains why the false positive happens, how often, what to do next, and how to run a screening program so one cross-reaction does not become a wrong decision.

TL;DR

• Sertraline is one of the best-documented medications that can trigger a false-positive benzodiazepine result on urine immunoassay screens.
• The cause is cross-reactivity: the test antibody binds a compound in the urine that looks enough like a benzodiazepine.
• A screening result is presumptive. Confirmation by GC-MS or LC-MS/MS can exclude or confirm a real benzodiazepine.
• Tell the collector, medical review officer or prescriber about your sertraline before the confirmation, and keep your prescription record handy.
• Programs that screen should treat every non-negative as unconfirmed and send it to confirmation before any action.

Table of Contents

• Why sertraline can look like a benzodiazepine
• How common is it?
• What the evidence says in plain terms
• Other medications that can trigger the same result
• What to do if you take sertraline and get a positive
• What to do if you run the program
• A worked example
• Our perspective
• Choosing a screening product for your program
• FAQ
• Sources

Why sertraline can look like a benzodiazepine

Most point-of-care and high-volume lab screens are immunoassays. They use antibodies designed to bind benzodiazepines and their metabolites. An antibody is a shape-matcher, not a chemist. If another molecule in the urine has a similar enough shape, the antibody may bind it and the test reads positive. The CDC’s urine drug testing guidance describes the standard workflow: immunoassays are used as screening tests, and laboratory-based gas or liquid chromatography/mass spectrometry is used primarily to confirm positive results.

An academic review of urine screen interferences puts the limitation plainly: immunoassay results are presumptive until confirmed by an independent chemical technique, and the same review notes that these assays can cross-react with both structurally related and unrelated compounds.

Sertraline does not need to be a benzodiazepine to cause this. Its breakdown products, including a hydroxyl ketone metabolite, are what some assay antibodies appear to latch onto. For a deeper look at the mechanism, see our explainer on immunoassay cross reactivity and the broader piece on how immunoassay screening works.

How common is it?

It is not rare in the data we can point to. A two-year retrospective chart review at a U.S. hospital looked at urine screens with benzodiazepine-positive results in patients with no benzodiazepine prescription. Of 98 false-positive results, 26 (26.5%) were associated with sertraline. The authors worked with one widely used assay formulation, so the figure describes that setting and does not predict your result on a different test.

The same paper explains why results differ by product. Older CEDIA formulations cross-reacted with sertraline, and Abbott AEROSET and ARCHITECT assays also produced sertraline-associated false positives. Roche later released an improved formulation described as not cross-reacting with sertraline’s inactive hydroxyl ketone metabolite.

The practical takeaway: taking sertraline does not guarantee a false positive. Whether it happens depends on the assay, the cutoff, the dose and how concentrated the urine is.

What the evidence says in plain terms

Other medications that can trigger the same result

Sertraline is not alone. A clinical reference on benzodiazepine screens names the antidepressant sertraline and the anti-inflammatory oxaprozin (Daypro) as associated with false-positive benzodiazepine results, along with a longer list of drugs that have been reported to produce false positives on benzodiazepine tests. That list includes some common over-the-counter and prescription products, such as diphenhydramine and aspirin. The same page advises that a patient with a positive screen and an active sertraline or oxaprozin prescription should have a GC-MS or LC-MS confirmation.

An academic review also points to efavirenz alongside sertraline, recommending that confirmatory GC-MS be performed when unexplained immunoassay results occur in people taking these two medications.

What about fluoxetine (Prozac), which people often ask about? The sources we reviewed for benzodiazepine screens name sertraline, not fluoxetine, as the antidepressant to watch. If you take fluoxetine or any other medication and get an unexpected result, the answer is the same as for sertraline: list every medicine, supplement and over-the-counter product you use, and ask for confirmation.

What to do if you take sertraline and get a positive

If you are the person tested, work through these steps in order.

1. Stay calm and do not argue the screen. A non-negative immunoassay is not a final finding. Ask what happens next and whether the specimen will be sent for confirmation.
2. Disclose sertraline, with dose. Tell the collector, the medical review officer (MRO) or the clinic. Do it before confirmation, not after.
3. Bring proof. A pharmacy printout or the prescription bottle, with your name, drug and fill date, is enough to start the conversation.
4. Ask for GC-MS or LC-MS/MS confirmation. These methods identify specific molecules. A real benzodiazepine will show up as a named compound. A sertraline cross-reaction will not.
5. Do not stop sertraline on your own. Antidepressants should only be changed under your prescriber’s direction. If you worry about future tests, ask your prescriber or pharmacist how to document the medication.
6. Keep the lab report. If the confirmation is negative for benzodiazepines, ask for a copy of that result.

If a confirmation does find a benzodiazepine, the question becomes whether you have a valid prescription for it. That is a conversation with the MRO or your prescriber, not a sertraline issue.

What to do if you run the program

Employers, clinics, treatment centers and justice programs see this from the other side. A few habits prevent most mistakes.

Treat every non-negative as unconfirmed

Never act on an immunoassay result alone. The FDA label for Zoloft states that a presumptive positive should be confirmed with a more specific method, and the CDC guidance describes the same two-step process. Our page on GC-MS confirmation covers why labs trust it for final results.

Collect medication information at the time of collection

A simple intake line asking the donor to list current prescriptions and over-the-counter medicines gives the reviewer context fast. It does not replace confirmation, but it tells the reviewer which cross-reactions to consider.

Know your assay and cutoff

Different products respond to different benzodiazepines at different cutoffs. Ask your supplier for the package insert and the cross-reactivity table, and read it before you deploy a product. Our benzo detection time guide walks through test windows, cutoffs and confirmation for labs.

Remember screens miss things too

Cross-reactions are one error type. The CDC also notes that immunoassays are qualitative and often have high cutoffs, which can give false-negative results. A clean screen does not prove a person took nothing. Specific drugs within a class may also need definitive testing: definitive testing may be indicated when identification of a specific drug within a class is desired.

Use a documented review path

Write down who reviews non-negatives, who contacts the donor, and what documents count. Our guides on identifying false positives and interpreting lab drug test results can serve as a starting point for that procedure. The false positive and lab accuracy guide adds more detail on how labs control error.

A worked example

A clinic runs a point-of-care urine cup on a new patient. The patient’s chart lists sertraline 100 mg daily and no benzodiazepine. The cup shows a faint line change on the benzodiazepine panel, read as non-negative.

The staff do not record the patient as using benzodiazepines. They record the screen as a presumptive positive, note the sertraline, and send the specimen for LC-MS/MS. If the lab reports no benzodiazepines, the screen is documented as a likely cross-reaction, and the treatment plan continues without a false accusation. If the lab does report a benzodiazepine, the clinic has a real finding to discuss, and it got there with a method that names the drug.

The point is the order of operations: screen, flag, confirm, then decide.

Our perspective

We sell screening tests, and we want our customers to use them the way they were designed: as a fast first step, not a verdict. A sertraline cross-reaction is a good example. It does not mean immunoassay screening fails. It means a screen needs a confirmation path and a person who knows how to read the result.

Most of the clinics, treatment programs and employers we supply handle this well. They choose a panel that fits their population, read the insert, record the donor’s medications, and send every non-negative to a lab. That workflow keeps the speed of on-site testing and removes the risk of a wrong call.

If you screen for benzodiazepines, we would rather you buy a test and use it properly than skip screening because of one known interference. Fast results at a fair price let you test more often, catch real problems earlier, and keep confirmation testing for the specimens that need it.

Justin

Choosing a screening product for your program

If you need benzodiazepine screening on site, we carry options for different volumes and settings. Single-analyte strips such as our benzodiazepine BZO test strips suit a targeted check. Multi-panel cups and dip cards suit intake and routine monitoring, and our 10 panel dip card and 12 panel dip card are common starting points. Our shop lists the full range, and we offer bulk discounts and custom quotes for larger programs.

Whatever you pick, keep the package insert with your program records and plan confirmation for every presumptive positive. We describe our tests as screening tools, and our product pages list the cutoffs and panels for each.

FAQ

Will Zoloft make you test positive on a drug test?

It can, but only for certain screens. Sertraline is documented to cause false-positive benzodiazepine results on some urine immunoassays, according to the FDA label. It is not expected to cause a true positive on a confirmation test for benzodiazepines, because GC-MS and LC-MS/MS identify the specific molecule.

What medication can give a false positive for benzodiazepines?

Sertraline and oxaprozin are the two most often named. Clinical references also list others, including some antihistamines and anti-inflammatory drugs. Because the list is long, tell the reviewer about every medicine you take, including over-the-counter products.

Can fluoxetine cause a false positive on a drug test?

The sources we reviewed for benzodiazepine screens point to sertraline rather than fluoxetine. Still, any unexpected non-negative should be confirmed by a laboratory method, whatever medication you take. Give your prescriber and the reviewer your full medication list.

How do I prove a positive was caused by sertraline?

You usually do not have to prove the cause. A confirmation test that finds no benzodiazepine shows the screen was a cross-reaction. Bring your prescription record so the reviewer can connect the two.

Should I stop taking sertraline before a drug test?

No, not without your prescriber’s direction. Stopping an antidepressant on your own can cause problems, and a confirmation test already protects you from a false positive. Disclose the medication and ask for confirmation instead.

Sources

• Zoloft (sertraline) FDA prescribing information
• False-Positive Urine Screening for Benzodiazepines: An Association with Sertraline? (PMC)
• CDC: Urine Drug Testing
• False-Positive Interferences of Common Urine Drug Screen Immunoassays: A Review
• Labcorp definitive drug testing guide
• What can cause a false positive urine drug screening for benzodiazepines? (MedCentral)
• False-Positive Urine Screening for Benzodiazepines: A Two-year Retrospective Chart Analysis (ResearchGate)

Recommended

• Benzo Detection Time for Labs: Test Windows, Cutoffs, Confirmation
• How to Identify False Positives on a Drug Test