Combating Drug Test False Positives: Busting the 7 Most Frustrating Myths

September 20, 2023

Case managers and court officials know the struggle: drug test false positives come up far too often in court cases and counseling discussions. They undermine and stall recovery and sobriety efforts and leave professionals second-guessing the data instead of providing the treatment their clients need.

But is drug testing as unreliable as it seems? Our experts have heard countless stories and have answered concerns over drug test false positives, both for the PharmChek® Sweat Patch and for other testing methods.

We’re answering these questions to bust some of the biggest myths and misconceptions around false positives in drug testing and to uncover the real problem with test results.

The Truth About Drug Test False Positives: Busting Myths

There’s plenty of misinformation about drug tests. One of the most common reasons donors give for false positive drug test results is that the tests simply aren’t reliable, which is only a half-truth.

Myth 1: You Can't Rely on Drug Test Results

This myth has proliferated for decades because of some basic shortfalls behind the drug testing methods courts and recovery programs most commonly use. Drug tests like on-site urinalysis and dip-strip instant testing are known to produce false positives, but not because they are unreliable. It’s because these methods are presumptive screening tools that identify different chemical compounds than confirmation testing by mass spectrometry.

And while we may commonly call them false positives, that term is not entirely accurate. Matt Hartley, PharmChek®’s Senior Account Manager, says it’s important to be more specific about the terminology.

“Due to cross-reactivity, screening tests can be triggered by substances other than specific illicit drugs. But legitimate false positives are only an issue in the screening phase.”

Once you use LC-MS/MS (liquid chromatography-tandem mass spectrometry) to analyze a specimen, that confirmation is accurate every time

Matt Hartley, Senior Account Manager

The results of these screening tests can sometimes be incorrect, but it isn’t because the tests themselves are bad. It’s because of the science behind the methods.

“Once you use LC-MS/MS (liquid chromatography-tandem mass spectrometry) to analyze a specimen, that confirmation is accurate every time,” says Hartley.

The Science Behind Drug Testing

Every drug testing method relies on the detection of chemical markers that correlate with specific substances. The methods look for parent drugs, direct metabolites of those drugs, or antigens and antibodies the body creates in response to the presence of the drugs.

The results of these different testing methods create what people see as false positives. In reality, we’re seeing the difference between degrees of accuracy in what tests are designed to identify.

“It’s like a lock-and-key set,” says Doug Crook, PharmChem’s toxicology specialist. “Closely related drugs are like keys that fit in a lock but don’t turn the mechanism. Only the correct key, the exact chemical match, will open the lock. Screening finds a key that fits the lock. Confirmation proves that the key opens that lock.”

Myth 2: Prescription and Over-the-Counter Medications Cause Drug Test False Positives

Enzyme Immunoassay (EIA) screening can return positive if a drug within the “family” of a certain illicit substance is present. In these cases, some legal prescriptions and over-the-counter medications could initially screen as illicit substances within the same chemical group. Until a confirmation test is performed, the results shouldn’t be considered conclusive.

As Crook states, “A positive screen is different from a confirmed positive. Those tests look for different things, and the immunoassay can pick up on chemical signatures that look a lot like illicit substances. But if all one does is an EIA (immunoassay screen) and doesn't confirm it with LC-MS/MS, the results aren’t complete.”

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The same can be said for prescription drugs that are chemically identical to illegal drugs but have been standardized for specific uses.

According to sales rep Jen Rankin, “Pharmaceutical-grade methamphetamine hydrochloride can be used legally in specific situations, but it’ll show up as meth from our lab. That’s not a false positive; it’s a true positive. More precise testing methods, even though the results may be unexpected, won’t confirm drugs that aren’t the drugs we’re looking for.”

More precise testing methods, even though the results may be unexpected, won’t confirm drugs that aren’t the drugs we’re looking for.

Jen Rankin, Business Development & Sales

Instead of relying on screening alone, courts and recovery programs should require confirmation through gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). These methods take advantage of the unique chemical signature inherent in every compound, including both parent drugs and their direct metabolites. No two signatures are identical, so when this confirmation test is performed, the results are accurate every time.

Matt Hartley puts it this way:

“Think of a subdivision. There are a bunch of different ‘neighbors’ (pseudoephedrine, methamphetamine, amphetamine) that live close together. Meth and amphetamine are next-door neighbors. Screening detects a ‘neighborhood’ and can get down to just a few houses within a subdivision. LC-MS/MS is like using GPS comparatively.”

If you can identify a drug with this precision, you no longer have to worry about false positive results.

Myth 3: Indirect Exposure Causes False Positive Drug Test Results

Court and recovery programs also encounter claims of drug test false positives from environmental or indirect exposure. Whether it’s secondhand inhalation, skin contact, or even intimate relations, donors claim that their positive test results are not a product of ingesting but of simply coming into contact with them. However, the science proves otherwise.

According to sales rep Kimberly Henderson, “The number one excuse we hear is that someone had intimate relations with a drug user. That’s their reason for a positive test result. But that’s not how it works.”

Physical contact isn’t enough to demonstrate use. PharmChek®’s medical-grade adhesive membrane keeps any outside contaminants, including drugs, from reaching the absorptive pad. Likewise, excuses like hair clippers, swimming in contaminated water, or drug-laced bed sheets all fall flat.

“When our test comes back positive, it’s confirmed by LC-MS/MS. There’s no doubt that the donor has used drugs,” says Hartley.

Why Courts and Recovery Programs Choose Screening Instead of Confirmation Tests

Still, even when they know the disadvantages of screening without confirmation, recovery programs and drug courts often choose EIA screening for much of their program needs. But why would this be the choice?

Far too often, it comes down to time, money, and staying within comfort zones.

Myth 4: Fast Results Mean Fast Processing and Better Treatment

One of the top reasons programs choose screening tests over confirmation tests is turnaround time. When working within tight timelines, sometimes a screen is all that is necessary to prove sobriety.

Sales rep Kimberly Henderson sees this when talking with agencies.

“Instant results are more satisfying and more efficient.”

But this doesn’t always work out for the courts or programs. And in the long run, it doesn’t always work out for the donors.

“There's a difference between trying to catch the person and trying to help the person. Having the right goal improves your process. Waiting means getting the true result,” says Henderson.

If the screen returns positive but is not confirmed, courts can incorrectly punish donors.

There's a difference between trying to catch the person and trying to help the person. Having the right goal improves your process. Waiting means getting the true result.

Kimberly Henderson, Business Development and Sales

Murray Brooks, our business development and sales leader, agrees.

“Instantaneous results are the desire in many cases. When officers overseeing participants are already swamped with responsibilities, they may only have time to collect enough information to check the box.”

But time scarcity shouldn’t hinder a participant’s progress. Sample collection should be simple, but that’s not always possible with urine, blood, saliva, or hair tests.

Myth 5: Expensive Tests Aren't Any Better Than Cheap Ones

Another common reason for using EIA screening without confirmation is that they’re inexpensive. That low cost is far easier to justify for high-volume testing needs. The thought is that the convenient and inexpensive testing works the same as more costly LC-MS/MS confirmatory tests. Unfortunately, this belief isn’t accurate.

Hartley states, “The PharmChek® Sweat Patch is, plain and simple, more reliable. You’ll see false positives in EIA screening, but not in LC-MS/MS confirmation. You have a far greater chance of a false negative.”

The difference between LC-MS/MS and rapid EIA testing leaves a significant chance for inadequate treatment, inaccurate results, and unnecessary consequences in some cases. Although it may seem more cost-effective to skip confirmation testing, it is without a doubt better for both donors and their case managers and counselors.

Myth 6: More Established Methods Are More Accurate

Many programs have used the same urine testing method for years. And an established system is often hard to overcome. It’s one of the objections our sales representatives hear when drug courts or recovery programs turn down new methods, including the PharmChek® Sweat Patch.

Richard Combs, who manages our sales and customer support, believes that bias keeps agencies from implementing other methods.

“What people are used to is their bias. PharmChek® tests continuously and always goes to confirmation if the specimen tests positive at screening, so our results are always accurate. There’s no next step or further test.”

PharmChek® tests continuously and always goes to confirmation if the specimen tests positive at screening, so our results are always accurate. There’s no next step or further test.

Richard Combs, Sales and Customer Support

That accuracy can be a double-edged sword for new PharmChek® customers, especially since the results could differ vastly from what they’ve experienced in the past. The difference, though, is often not more false positives. Instead, the PharmChek® Sweat Patch uncovers many false negatives that have likely gone undetected previously.

Drug Test False Negatives: A Much Bigger Problem

Drug courts and recovery programs hear about false positives most frequently, but our experience is that false negatives are far more common.

From inadequate screen cutoff levels to inaccurate detection of antigens or metabolites, simple screening tests like urine and saliva tests are more likely to come out erroneously negative than positive.

But with more stringent cutoffs and LC-MS/MS confirmation for results, those false negatives almost disappear entirely. By eliminating false negatives, professionals and case managers are better equipped to address donor issues that can hinder progress.

Myth 7: Urinalysis Results and PharmChek® Sweat Patch Results Contradict Each Other

Courts that have added LC-MS/MS confirmation testing to their EIA screening often see contradictory results between the two methods. Donors often take advantage of this contradiction, stating that neither result should be trusted. But our toxicology experts know that these contradictions occur, and for good reason.

“Screening and confirmation are two different types of testing,” says Henderson, “and only one is always accurate.”

Henderson expands: “New customers are often shocked by the results they suddenly start getting. What used to be mostly negatives is suddenly lots of positives. They don’t like the results, and they may even struggle to believe them, but the truth is that their old testing method wasn’t designed to test for use continuously. The PharmChek® Sweat Patch does just that. There are no gaps in detection.”

PharmChek® stands behind the accuracy of every result because our dedicated lab starts with more stringent screening standards. This is the most significant difference between the Sweat Patch and other methods.

How the PharmChek® Drug Patch Eliminates Drug Test False Positives and Negatives

Drug screening alone isn’t enough to be confident of your test results. And courts, programs, and policies that rely on screening for treatment decisions will find themselves unequipped to provide the support their clients actually need.

Hartley says, “If you’ve depended on immunoassay screenings alone in a program, you might get negatives and think that’s enough. But the truth is that if someone’s freedom is at stake, that confirmation should be done. A cheap test isn’t designed to confirm. It needs to go to a lab for a proper evaluation.”

if someone’s freedom is at stake, that confirmation should be done. A cheap test isn’t designed to confirm. It needs to go to a lab for a proper evaluation.

Matt Hartley, Senior Account Manager

The PharmChek® Sweat Patch is the next step in recovery treatment and drug court policies. The innovative collection method, paired with industry-leading testing and confirmation for every specimen, helps clients achieve their goals faster—and with more precision.

Unrivaled Accuracy

Every specimen we receive goes through a 2-step confirmation process, starting with an EIA screen. If a screen returns positive, it automatically moves forward to LC-MS/MS confirmation. You receive the final results without questions about accuracy, false positives, or false negatives.

No Adulteration

Unlike urinalysis and dip-strip testing, there’s no way for a donor to dilute the PharmChek® Sweat Patch. There’s no more doubt around the accuracy of a specimen, giving you the information you need to keep your clients on course for sobriety and recovery.

The PharmChek® Difference

How confident are you in your program's testing results? Without 24-hour accountability and a tamper-evident design, you could be missing the right information.

Noninvasive Collection

The PharmChek® Sweat Patch is a trauma-informed best practice. Our patch is gender-indifferent, does not require direct observation of private body parts to collect a sample, and needs no medical training to administer. The PharmChek® Sweat Patch allows your program to drug test efficiently, safely, privately, and with minimal staffing requirements.

No matter how big or small your court or recovery program is, you can use the PharmChek® Sweat Patch with ease and confidence.

Test-Forward Accountability

PharmChek®'s insensible sweat collection is the only method that provides a test-forward model. You won’t be looking for past use, and your donors won’t have past use as an excuse for positive results. From the moment you apply PharmChek® to the moment you collect it—up to 10 days of continuous sample collection—your clients know they’re accountable for their choices, from vaping to relapse.

Our sample collection tracks drug use from 24 hours prior to patch application until it is removed seven to ten days later (or longer if paired with the PharmChek® Overlay), giving you a clear picture of your client’s treatment progress—all without doubts or questions.

Court-Supported Results

The PharmChek® Sweat Patch boasts 30-plus years of court-supported results, the only patch-based collection and testing system to come with this kind of legal backing. Judges, case managers, and recovery counselors have trusted PharmChek® for continuous monitoring for decades.

The results are faster recovery, more accountability, and improved treatment plan coordination compared to urine, dip-strip, blood, or hair testing.

It's Time for a Better Testing Method

If you’re wondering if your recovery or drug court testing program is truly effective without confirmation testing, the truth is that you’re more than likely missing opportunities daily to support your clients properly. See what our test-forward model can do for your program today.

Start here:

1: See What Courts Have to Say about PharmChek®

Countless courts across the country have confirmed the accuracy of PharmChek®’s test-forward method. Read the court cases to learn what judges, case managers, and recovery workers have to say about the Sweat Patch.

2: Join Us for Training Tuesdays

Kimberly Henderson hosts conversations with professionals and experts to help answer questions, resolve concerns, and keep you up-to-date with the latest industry trends. Training Tuesdays are completely free, and they provide incredible value when combined with our online training and certification.

3: Speak to One of Our Sales Representatives

If you’re ready to incorporate PharmChek® into your program, our sales representatives are ready to get you started. Talk with a rep today to learn more about testing, certification, and pricing. It’s never too late to start testing forward.

Test Forward. Starting Today.

When you choose PharmChek® for your recovery needs, there's no more doubt. We can get you started today.