BAR on a drug test stands for barbiturates, a class of sedative drugs that slow down the central nervous system. You’ll typically see this abbreviation on a multi-panel drug screening alongside other shorthand codes like AMP (amphetamines), BZO (benzodiazepines), THC (marijuana), and COC (cocaine). If your test results or test cup lists “BAR,” it’s checking for the presence of barbiturate compounds in your system.
What Barbiturates Actually Are
Barbiturates are prescription sedatives that were widely used from the early 1900s through the 1970s for anxiety, insomnia, and seizures. They’ve largely been replaced by safer alternatives, but several are still prescribed today. The FDA-approved barbiturates currently in clinical use include phenobarbital (for seizures), butalbital (for tension headaches), pentobarbital, methohexital, primidone, and amobarbital.
The one most people encounter without realizing it is butalbital, which is a key ingredient in popular headache medications. The combination of butalbital with acetaminophen and caffeine is commonly prescribed for tension-type headaches. If you take one of these headache prescriptions and then have a drug test, it will likely trigger a positive BAR result.
Is BAR on a Standard Drug Test?
Barbiturates are not part of the standard federal 5-panel drug test. The mandatory federal workplace testing guidelines from SAMHSA only require screening for marijuana, cocaine, opiates, amphetamines, and phencyclidine (PCP). Barbiturates don’t appear on that list because they may be legally prescribed, and their recreational use has declined significantly over the decades.
However, many employers and organizations use expanded panels (7-panel, 10-panel, or 13-panel tests) that do include barbiturates. A typical 13-panel test, for example, checks for amphetamines, barbiturates, benzodiazepines, cocaine, PCP, THC, opiates, oxycodone, methadone, fentanyl, meperidine, propoxyphene, and tramadol. So whether BAR shows up on your test depends entirely on which panel your employer or testing organization selected.
Screening Cutoff Levels
Because barbiturates aren’t covered by the federal mandatory guidelines, the scientific community has established its own recommended cutoff. The standard initial screening cutoff for barbiturates is 300 ng/mL in urine. Anything below that threshold registers as negative, even if trace amounts are technically present. This cutoff is the same level used for cocaine and methadone screening.
If the initial screening comes back positive, a confirmation test can be requested. The initial test uses an immunoassay method, which is fast but can occasionally react to similar-looking compounds. Confirmation testing uses gas chromatography-mass spectrometry (GC/MS), a far more precise technique that can identify exactly which barbiturate is present and rule out false results. Positive immunoassay results are considered presumptive until confirmed by GC/MS.
How Long Barbiturates Stay in Your System
Detection windows vary dramatically depending on which barbiturate you’ve taken. Short-acting barbiturates like secobarbital are detectable in urine for roughly 1 to 2 days. Intermediate-acting ones like pentobarbital show up for 2 to 4 days. Phenobarbital, a long-acting barbiturate commonly prescribed for epilepsy, can be detected for 10 to 20 days after your last dose.
This wide range matters if you have a legitimate prescription. Someone taking phenobarbital daily for seizure control will test positive for weeks after stopping, while someone who took a single dose of a butalbital headache medication may clear the test within a few days.
What Can Cause a False Positive
A handful of non-barbiturate substances can trigger a false positive on the initial immunoassay screen. Phenytoin, an anti-seizure medication, is one documented cause. Common over-the-counter pain relievers including ibuprofen, naproxen, and fenoprofen have also been shown to produce false positives for barbiturates in rare cases, particularly with chronic use.
This is exactly why confirmation testing exists. If you test positive for BAR and you haven’t taken any barbiturate medication, requesting a GC/MS confirmation test will distinguish a true positive from a cross-reaction caused by another substance. The confirmation test can identify specific barbiturates individually, including amobarbital, butabarbital, butalbital, pentobarbital, phenobarbital, and secobarbital.
What a Positive BAR Result Means
A positive result simply means barbiturate compounds were detected above the cutoff threshold. If you have a valid prescription for a barbiturate-containing medication, this is expected and can typically be resolved by providing documentation of your prescription to the medical review officer who oversees the testing process. Legitimate prescriptions for phenobarbital or butalbital headache medications are among the most common explanations for positive BAR results.
If you’re taking any medication and aren’t sure whether it contains a barbiturate, check the label or ask your pharmacist before your test. Combination headache medications are the easiest to overlook because the barbiturate component isn’t always obvious from the brand name alone.